I am still figuring out how other apps implement SharePlay, but I'm reasonably happy with how it works in @broadcastsapp now in this initial version. You can start up a session over iMessage, then any participant can start playback of a station. Station name/address/artwork is shared directly through SharePlay, doesn't need to already be in your library. Could make for a fun 'watch party' mode for audio-only streams like podcasts or live events