I'm not quite sure what you're describing here, the summary is that I use the inbox model to send shared keys to members. Those invites have relay hints to help them find the group. Everything is wrapped using the nip 59 draft. You can read the spec here:

GitHub

Add closed communities by staab · Pull Request #875 · nostr-protocol/nips

This is an attempt at superseding #706 and incorporating existing NIPs for community definitions and member lists. The design is worse in many ways...

Thanks for liking coracle! The new release removes several old features which I hope to revisit later.