For anyone following this thread, the ability to do this should be launched in the next app update. It is currently in testing to allow us to set rules based on change of the HMS state.
So you would set up a rule that whenever the state “Switches to Home” or “Switches to Away” as the trigger, you would set the action as “Turn on notifications” and when it “Switches to Disarmed” you would set it turn off notifications. You can tell it to do it for every device, or just select individual devices you want affected.
I don’t know when the next app update will launch, but the Release candidate and the Beta app version prior to it have had this ability (I’ve tested it out), so I expect you will all see it soon. 