I concur with Sandpiper. Through Rules you will disable the chime for all zones for your time setting.
Whenever some event happens
Then turn off chime
Then turn on output 100 for 15 minutes
Whenever output 100 turns off
Then turn on chime
If you want the chime change to be silent, you may want to take out the "Chime is off" voice announcement in the Automation, Voice edit menu in ELKRP.