The abuse of multi-town is already a thing, simply use an alt and give toggled perms, bam instant access to the full town.
#1 Allow use to oath to multiply towns, and the Authority gain from a player is split to each town. (50/50 for 2 towns, 33/33/33 for 3 towns, ect).
Additional
#2 Also add a perm if that color sees town-chat or not. (I do want to see multiply-town chats)
#3 New town objects that allows to make pseudo claims that are owned by the town and give access to a single player oathed or un-oathed.