or maybe at least the posts wouldn’t be replicated, but there would only be one community, and when you visit it, posts for the community are downloaded from your primary instance, as well as other instances based on some configuration that makes sense.
i think enough people want the feature that the benefit would be worth it
you actually wouldn’t have to limit it to exact same name if you’re making a front-end thing, if you allow for the user to configure their “merged communities”