Can the inclusion of a specific hashtag on a note broadcast it to a relay and anyone who has that relay can interact with it solely on that relay? So it’d still show in non supporting clients but if you wanted “dog relay”, you could open a client and narrow down to just the dog relay which would only include posts initiated by the tag or native to the relay?

Completely spitballing as I’m not great with how relay/kinds/hashtags work in a Nostr context. Just an idea.