know how you get raiders and such right?
why not a setting that disables the ability to group up and such out right and makes all survivors hostile/unfriendly, call it "Rival Survivors" and its main function is to add a new enemy type essentially but one that is more intelligent than simple zombies or wildlife.

now you might be thinking "you can do that with settings" and you would be right!
but what i am suggesting is when this Rival Survivors mode is enabled all the grouping, all the storage settings (except base zone) and interactions are all disabled so you have an even lighter version of Subpar survivors thats purely for enemy combat.

there are folks i know who install this mod purely because of your tweaks for the survivors as enemies, so why not capitalize on it and have it as a feature that uses less resources eh?

of course thats entirely up to you but more options for play never hurts am i right? :D