Repeat Task (Message)

[Rossd]

I was hoping to solict some ideas on a "repeating" task.  I have two rules.
 
Rule 1. When garage is open send "Garage Open" email to [email protected]
Rule 2. When garage is closed send  "Garge Closed" email to [email protected]
 
I would like to add the following:
 
Every X mins reassert Rule 1 until Rule 2 fires.  I assume I want to add starting a timer to rule 1 or create a new rule based on a timer and the conditions of rule 1?
 
Anyway, I was hoping to get some ideas on the best way to repeat these messages?
 
Thanks,
Ross