There is no "Avoid List" per se. Avoid is an attribute among other attributes for channels, departments/sites or systems.
You can get to where you want to go assuming you have created a Favorites List with known talkgroups. Create a new Department and give it a name something like "Searched". If you use Location Control, be sure there is a valid location near you associated with this new department.
Then add one channel to the new department, perhaps a channel unlikely to have much traffic. Following that, Avoid all other departments for the system and set the system for ID Search. The scanner with then stop on any new or "unlisted" talkgroups.
You would need, or at least I think you need, that one channel so you do not get a "Nothing to Scan" message.
