None currently, but I'm almost ready to ship the update that adds relay-based communities. It's not going to follow any NIP, it will a Satellite specific thing. Although, as I've said before, I think what @ hodlbod is doing with Flotilla is directionally the right approach, and I'm trying to make it as interoperable as possible. Actually basic relay feeds are actually working already (though it's sort of a hidden easter egg right now since I haven't wired up the UI) e.g.

Satellite

satellite.earth