Since you state "certain" ADT messages, are there others for the same destination system that should be sent regardless of the time of day, or should all messages stop from 10:30pm through 10:30am?
If it's all messages, a schedule should do the trick. It's created under "Additional Settings" for the BO. A schedule of START:*-*-*T10:30:00,STOP:*-*-*T22:30:00 will enable and disable the operation at the times you've specified.
On an unrelated note: Things are pretty dead here on Google Groups. Most of the action is now over at the Intersystems Developer Community:
https://community.intersystems.com/. You'll likely get answers much faster there.