No built-in way. Not anymore than multiple subreddits for the same purpose. Eventually one will become the more popular. It’s nothing new.

Treat them like different subs like /r/askreddit and /r/trueaskreddit

One will become more popular over time. Even still, one might attract one kind of community and the other a different kind of community. That’s sort of why there are different instances right? It’s due to a fundamental difference between Lemmy and Reddit.

I don’t believe there’s a way to bring them together beyond subscribing to both and using your subscription view. There are Github issues open about this idea, so it’s being considered but hard to say if and when they’ll be added.

That thread does raise some good points about automatically grouping by name. Some instances may use a name maliciously or ironically, their posts would end up in the same group.

And we don’t necessarily want to prevent fragmentation, it can be a good thing to have multiple sources. If lemmy world because problematic and gets defederated, you won’t lose asklemmy as you’ll still have the Lemmy ml asklemmy community.

There currently is no way - and in my opinion should be no way to prevent duplicate communities across instances. One community will eventually become popular enough to be considered the de facto community, though we shouldn’t force interaction with an instance simply because they have dibs on a community name.

Less discerning users can subscribe to both communities.

Hopefully one will die, so that the other will flourish or maybe both will flourish?

Cool be rather cool if communities could merge together a cross instances.

I see this as a feature and not a bug. A reddit sub can be taken over by a small but vocal group of users or mods rendering the sub distasteful to the general public. Very little can be done once that happens but here you can “vote” with your subscription.