Got me thinking it might be possible with a transition trick set-up. If eg R8 is recording main and T8 is playing R8 with REL INF, loop ON, and you switch to an empty pattern on the same part, wouldn’t it just keep on playing?
Too late for me to test today but I think it could work, not a basic solution really but it’s possible you could get this kind of behaviour if you sacrifice a track. I’ve linked to a thread about the transition trick if you don’t know what that is.