I think what makes more sense is for lemmy/kbin instances to show all instances under the same !community as one from many sources, with the ability for the instance admin to filter out the source instances that are deemed innapropriate.
You could have gaming@kbin.social & gaming@lemmy.ml collectively treated as one !gaming in the instance, with different sources just like the way comments already work. Then when another community gaming@evil.rude spins up, it should be automatically interpreted as !gaming until the admin filters them from their instance.