What's the story on posting to (and reading from) a subset of relays in an organized manner?

Example use case: you have a neighborhood relay where local residents post _some_ of their notes, and other residents can view notes from _just_ that relay at will. (Effectively nostr-NextDoor but without having to build anything)

As far as I can tell this would be enabled merely by some client features ("post to..." On note creation, "Relay xyz filter" on feeds, etc.). Am I wrong about that? Do any current clients offer this?

#askNostr