We can easily turn the tree into Nostr events if there is demand for that, but I can't imagine that happening. It works already with the Nostr-based invites that is integrated into https://flotilla.social,

Jumble

A user-friendly Nostr client for exploring relay feeds

and

Fevela

A Nostr social client that give you back full control of your attention and time with an innovative interface

you get an invite code which is a Nostr event and you can later publish a Nostr event to get admitted into the relay.