I mean, they share the backend communities/magazines, so it shouldn’t matter where a given one lives, but you can turn off showing federated content and you’ll only see stuff on kbin.social. Won’t see stuff on other kbin instances, though.

Click the little button with three connected nodes. In the desktop Kbin Web UI, it’s in the right-hand sidebar. On mobile, it’s near the bottom.

Beneath that, you’ll see a “Federation status”. Click “off”.

Don’t forget to turn it back on later, though.

You can also browse the list of magazines on kbin.social. Those will all be local.

You can also browse just content on one instance, like only communities on one Lemmy or kbin server, by using the /d/ prefix. So, to view stuff on fedia.io, which also runs kbin, you can do this:

https://kbin.social/d/fedia.io

Or you could just browse to fedia.io’s Web UI:

https://fedia.io/

And then do the same “toggle off federated content” thing to see only content on fedia.io.

I don’t think that there’s a convenient way to see all content from all federated kbin servers but to exclude content on federated Lemmy servers, though.