JonW
Here are screenshots of my mobile app.  The first two are the home screen, the third is a drill down of the grouped lights after clicking the "Lights" category, and the forth is the screen shot after clicking on the Family Room group under lights. 
 
https://www.dropbox.com/s/8g89y2945n4s2ao/OHMobileScreen1.png?dl=0
 
https://www.dropbox.com/s/hkm7vd395y0zp39/OHMobileScreen2.png?dl=0
 
https://www.dropbox.com/s/va19txt0tukd51h/OHMobileScreen3.png?dl=0
 
https://www.dropbox.com/s/4p7z41vpjop7ic5/OHMobileScreen4.png?dl=0
 
The organization (groups) and the icons for the lights are set up on the items file.  Icons can also be set at the sitemap level as well.  Here is my items file for my lighting.  The top level of the item file is the "group" roll up.  You'll see the group name listed by each item (by room name).  The top group nests the lower groups.
 
 
Group:Switch:OR(ON, OFF) Lights     "Lights [%s]" (All)
Group:Switch:OR(ON, OFF) Lights_FamilyRoom  "Family Room [%s]"   (Lights)  
Switch FamilyRoom_Switch       "Family Room [%s]"     (Lights_FamilyRoom)  {channel="omnilink:room:home:1:switch"}
Switch  FamilyRoom_OnScene  "Scene On [%s]"    (Lights_FamilyRoom)  {channel="omnilink:room:home:1

n"}
Switch  FamilyRoom_OffScene  "Scene Off [%s]"  (Lights_FamilyRoom)  {channel="omnilink:room:home:1

ff"}       
Switch  FamilyRoom_Scene_A   "Scene A [%s]"    (Lights_FamilyRoom)  {channel="omnilink:room:home:1:scene_a"}
Switch  FamilyRoom_Scene_B   "Scene B [%s]"    (Lights_FamilyRoom)  {channel="omnilink:room:home:1:scene_b"}
Switch  FamilyRoom_Scene_C   "Scene c [%s]"    (Lights_FamilyRoom)  {channel="omnilink:room:home:1:scene_c"}
Switch  FamilyRoom_Scene_D   "Scene D [%s]"    (Lights_FamilyRoom)  {channel="omnilink:room:home:1:scene_d"}
Number FamilyRoom_State  "Family Room Lights [%s]" (Lights_FamilyRoom)  {channel="omnilink:room:home:1:state"}
Dimmer Lights_FamilyRoom_Ceiling_Switch  "Ceiling [%s]"  (Lights_FamilyRoom)  {channel="omnilink:upb:home:2:level"}
Dimmer Lights_FamilyRoom_FanLight_Switch  "Fan Light [%s]" (Lights_FamilyRoom)  {channel="omnilink:upb:home:3:level"}
Dimmer Lights_FamilyRoom_Lamp_Switch  "Lamp [%s]"      (Lights_FamilyRoom)  {channel="omnilink:upb:home:4:level"}
Dimmer Lights_FamilyRoom_CeilingFan_Switch   "Ceiling Fan [%s]" (Lights_FamilyRoom)  {channel="omnilink:upb:home:5:level"}
Dimmer Lights_FamilyRoom_NookLight_Switch   "Nook Light [%s]" (Lights_FamilyRoom)  {channel="omnilink:upb:home:6:level"}
Group:Switch:OR(ON, OFF)  Lights_Downstairs   "Downstairs [%s]"       (Lights)
Switch Downstairs_Switch      "Downstairs [%s]"  (Lights_Downstairs)  {channel="omnilink:room:home:9:switch"}
Switch  Downstairs_OnScene   "Scene On [%s]"    (Lights_Downstairs)  {channel="omnilink:room:home:9

n"}
Switch  Downstairs_OffScene  "Scene Off [%s]"   (Lights_Downstairs)  {channel="omnilink:room:home:9

ff"}       
Switch  Downstairs_Scene_A   "Scene A [%s]"     (Lights_Downstairs)  {channel="omnilink:room:home:9:scene_a"}
Switch  Downstairs_Scene_B   "Scene B [%s]"     (Lights_Downstairs)  {channel="omnilink:room:home:9:scene_b"}
Switch  Downstairs_Scene_C   "Scene c [%s]"     (Lights_Downstairs)  {channel="omnilink:room:home:9:scene_c"}
Switch  Downstairs_Scene_D   "Scene D [%s]"    (Lights_Downstairs)  {channel="omnilink:room:home:9:scene_d"}
Number Downstairs_State      "Downstairs Lights [%s]"  (Lights_Downstairs)  {channel="omnilink:room:home:9:state"}
Dimmer Lights_Downstairs_DwnStrHall_Switch "DwnStr Hall [%s]" (Lights_Downstairs)  {channel="omnilink:upb:home:11:level"}
Dimmer Lights_Downstairs_Foyer_Switch   "Foyer [%s]"       (Lights_Downstairs)  {channel="omnilink:upb:home:12:level"}
Dimmer Lights_Downstairs_FntRmOutlet_Switch "FntRm Outlet [%s]" (Lights_Downstairs)  {channel="omnilink:upb:home:13:level"}
Dimmer Lights_Downstairs_Study_Switch  "Study [%s]"  (Lights_Downstairs)  {channel="omnilink:upb:home:14:level"}
Group:Switch:OR(ON, OFF) Lights_Kitchen  "Kitchen [%s]"   (Lights)
Switch Kitchen_Switch      "Kitchen [%s]"  (Lights_Kitchen)  {channel="omnilink:room:home:17:switch"}
Switch  Kitchen_OnScene    "Scene On"      (Lights_Kitchen)  {channel="omnilink:room:home:17

n"}
Switch  Kitchen_OffScene    "Scene Off"    (Lights_Kitchen)  {channel="omnilink:room:home:17

ff"}       
Switch  Kitchen_Scene_A      "Scene A"     (Lights_Kitchen)  {channel="omnilink:room:home:17:scene_a"}
Switch  Kitchen_Scene_B      "Scene B"     (Lights_Kitchen)  {channel="omnilink:room:home:17:scene_b"}
Switch  Kitchen_Scene_C       "Scene c"    (Lights_Kitchen)  {channel="omnilink:room:home:17:scene_c"}
Switch  Kitchen_Scene_D       "Scene D"    (Lights_Kitchen)  {channel="omnilink:room:home:17:scene_d"}
Number Kitchen_State          "Kitchen Lights [%s]"  (Lights_Kitchen)  {channel="omnilink:room:home:17:state"}
Dimmer Lights_Kitchen_Sink_Switch   "Sink [%s]"  (Lights_Kitchen)  {channel="omnilink:upb:home:18:level"}
Dimmer Lights_Kitchen_Overhead_Switch  "Overhead [%s]"  (Lights_Kitchen)  {channel="omnilink:upb:home:19:level"}
Dimmer Lights_Kitchen_Chandalier_Switch "Chandalier [%s]" (Lights_Kitchen)  {channel="omnilink:upb:home:20:level"}
Dimmer Lights_Kitchen_Cabinet1_Switch   "Cabinet 1 [%s]"  (Lights_Kitchen)  {channel="omnilink:upb:home:21:level"}
Dimmer Lights_Kitchen_Ceiling1_Switch   "Ceiling 1 [%s]"  (Lights_Kitchen)  {channel="omnilink:upb:home:22:level"}
Dimmer Lights_Kitchen_Cabinet2_Switch   "Cabinet 2 [%s]"  (Lights_Kitchen)  {channel="omnilink:upb:home:23:level"}
Dimmer Lights_Kitchen_Ceiling2_Switch   "Ceiling 2 [%s]"  (Lights_Kitchen)  {channel="omnilink:upb:home:24:level"}
Group:Switch:OR(ON, OFF) Lights_Outside   "Outside [%s]"  (Lights)
Switch Outside_Switch     "Outside [%s]"    (Lights_Outside)  {channel="omnilink:room:home:25:switch"}
Switch  Outside_OnScene    "Scene On"       (Lights_Outside)     {channel="omnilink:room:home:25

n"}
Switch  Outside_OffScene    "Scene Off"     (Lights_Outside)     {channel="omnilink:room:home:25

ff"}       
Switch  Outside_Scene_A     "Scene A"       (Lights_Outside)     {channel="omnilink:room:home:25:scene_a"}
Switch  Outside_Scene_B     "Scene B"       (Lights_Outside)     {channel="omnilink:room:home:25:scene_b"}
Switch  Outside_Scene_C     "Scene c"       (Lights_Outside)     {channel="omnilink:room:home:25:scene_c"}
Switch  Outside_Scene_D     "Scene D"       (Lights_Outside)     {channel="omnilink:room:home:25:scene_d"}
Number Outside_State        "Outside Lights [%s]"  (Lights_Outside)     {channel="omnilink:room:home:25:state"}
Switch Lights_Outside_BackFlood_Switch  "Back Flood [%s]"    (Lights_Outside)  {channel="omnilink:upb:home:27:level"}
Switch Lights_Outside_FtPchLght_Switch  "Ft Pch Lght [%s]"   (Lights_Outside)  {channel="omnilink:upb:home:28:level"}
Switch Lights_Outside_GarageExt_Switch  "Garage Ext [%s]"    (Lights_Outside)  {channel="omnilink:upb:home:29:level"}
Switch Lights_Outside_BackPatio_Switch  "Back Patio [%s]"    (Lights_Outside)  {channel="omnilink:upb:home:30:level"}
Switch Lights_Outside_PoolLight_Switch  "Pool Light [%s]"    (Lights_Outside)  {channel="omnilink:upb:home:31:level"}
Switch Lights_Outside_GarageInt_Switch  "Garage Int [%s]"    (Lights_Outside)  {channel="omnilink:upb:home:32:level"}
Group:Switch:OR(ON, OFF) Lights_UpstairsHall    "Upstairs Hall [%s]"   (Lights)
Switch Lights_UpstairsHall_Switch  "Upstairs Hall [%s]"  (Lights_UpstairsHall)  {channel="omnilink:room:home:33:switch"}
Switch  Lights_UpstairsHall_OnScene   "Scene On"    (Lights_UpstairsHall)  {channel="omnilink:room:home:33

n"}
Switch  Lights_UpstairsHall_OffScene  "Scene Off"   (Lights_UpstairsHall)  {channel="omnilink:room:home:33

ff"}       
Switch  Lights_UpstairsHall_Scene_A   "Scene A"     (Lights_UpstairsHall)  {channel="omnilink:room:home:33:scene_a"}
Switch  Lights_UpstairsHall_Scene_B   "Scene B"     (Lights_UpstairsHall)  {channel="omnilink:room:home:33:scene_b"}
Switch  Lights_UpstairsHall_Scene_C   "Scene c"     (Lights_UpstairsHall)  {channel="omnilink:room:home:33:scene_c"}
Switch  Lights_UpstairsHall_Scene_D   "Scene D"     (Lights_UpstairsHall)  {channel="omnilink:room:home:33:scene_d"}
Number Lights_UpstairsHall_State      "Upstairs Hall Lights [%s]" (Lights_UpstairsHall)  {channel="omnilink:room:home:33:state"}
Dimmer Lights_UpstairsHall_StairCan_Switch  "Stair Can [%s]" (Lights_UpstairsHall)  {channel="omnilink:upb:home:35:level"}
Dimmer Lights_UpstairsHall_UpHallCans_Switch "Up Hall Cans [%s]" (Lights_UpstairsHall)  {channel="omnilink:upb:home:36:level"}
Dimmer Lights_UpstairsHall_UpendHall_Switch  "Up end Hall [%s]"  (Lights_UpstairsHall)  {channel="omnilink:upb:home:37:level"}
Group:Switch:OR(ON, OFF) Lights_MasterBed   "Master Bedroom [%s]"   (Lights)
Switch Lights_MasterBed_Switch       "Master Bedroom [%s]" (Lights_MasterBed)    {channel="omnilink:room:home:41:switch"}
Switch  Lights_MasterBed_OnScene     "Scene On [%s]"       (Lights_MasterBed)    {channel="omnilink:room:home:41

n"}
Switch  Lights_MasterBed_OffScene    "Scene Off [%s]"      (Lights_MasterBed)    {channel="omnilink:room:home:41

ff"}       
Switch  Lights_MasterBed_Scene_A     "Scene A [%s]"        (Lights_MasterBed)    {channel="omnilink:room:home:41:scene_a"}
Switch  Lights_MasterBed_Scene_B     "Scene B [%s]"        (Lights_MasterBed)    {channel="omnilink:room:home:41:scene_b"}
Switch  Lights_MasterBed_Scene_C     "Scene c [%s]"        (Lights_MasterBed)    {channel="omnilink:room:home:41:scene_c"}
Switch  Lights_MasterBed_Scene_D     "Scene D [%s]"        (Lights_MasterBed)    {channel="omnilink:room:home:41:scene_d"}
Number Lights_MasterBed_State        "Master Bedroom Lights [%s]" (Lights_MasterBed)    {channel="omnilink:room:home:41:state"}
Dimmer Lights_MasterBed_Overhead_Switch  "Overhead [%s]"   (Lights_MasterBed)    {channel="omnilink:upb:home:43:level"}
Group:Switch:OR(ON, OFF) Lights_Landscape  "Landscape [%s]" <outdoorlight>   (Lights)
Switch Landscape_Switch        "Landscape [%s]"         (Lights_Landscape)   {channel="omnilink:room:home:49:switch"}
Number Landscape_State         "Landscape Lights [%s]" (Lights_Landscape)   {channel="omnilink:room:home:49:state"}
Switch Lights_Landscape_HouseFront_Switch "House Front [%s]"     (Lights_Landscape)   {channel="omnilink:upb:home:51:level"}
 
Keep in mind the scene switches are not the way I want them.  The example on the second screen shot will be what those will look like in the near future. 
 
With the above item file I have the following sitemap.  Again, the lights are just a group name, nothing complicated. 
 
 
sitemap standard label="Miller Home (OH2)"{
Frame label="Security"{
//Switch item=Areas_House_Mode label="Select Mode" icon="shield" mappings=["Off"="Off","Day"="Day","Night"="Night", "Away"="Away","Vacation"="Vacation"]
        
Selection item=AlarmStatusSelect label="Select Mode" icon="shield" mappings=[0="Off",1="Day",2="Night", 3="Away",4="Vacation"]
        //Text item=ArmModeDisarm
        
        Text item=AlarmMode  label="Current Alarm Status"  icon="house"
Switch item=Buttons_Garage2Btn        label="Right Garage Door" icon="garagedoor" mappings=[ON="Push"]
Text item=Zones_GarageDrRight_Current label="Right Garage Door" icon="garagedoor"
Switch item=Buttons_Garage1Btn        label="Left Garage Door"  icon="garagedoor" mappings=[ON="Push"]
Text item=Zones_GarageDrLeft_Current  label="Left Garage Door"  icon="garagedoor"
Switch item=Buttons_ClsGateBtn        label="Gate"              icon="gate"       mappings=[ON="Push"]
Text item=Zones_Gate_Current          label="Gate"              icon="gate"
Group item=Zones   label="Unsecure Zones"  icon="house"
Group item=Areas   label="General Areas"   icon="house"
Switch item=FtDrLckStsFl_Flag mappings=[ON="Locked", OFF="Unlocked"]
Switch item=BcDrLckStsFl_Flag mappings=[ON="Locked", OFF="Unlocked"]
Switch item=GrDrLckStsFl_Flag mappings=[ON="Locked", OFF="Unlocked"]
}
Frame label="Occupancy"{
Group item=Occupancy
}
Frame label="Lights"{
Group item=Lights
Switch item=FamilyRoom_State label="FAMILY ROOM" mappings=[0="OFF", 1="ON", 2="A",3="B",4="C",5="D"]
Selection item=FamilyRoom_State label="FAMILY ROOM" mappings=[0="OFF", 1="ON", 2="A",3="B",4="C",5="D"]
}
Frame label="Outside"{ 
Switch item=PlPumpUnit_Switch label="Pool Pump"  icon="switch" mappings=[ON="On", OFF="Off"]
Switch item=PlSweepUnit_Switch  label="Pool Sweep" icon="switch" mappings=[ON="On", OFF="Off"]
Switch item=Lights_Outside_PoolLight_Switch label="Pool Light" icon="light" mappings=[ON="On", OFF="Off"]
Group item=Irrigation icon="grass" 
}
 
This binding is extremely new so I have been working to figure out some of the things myself (like the scene switches).