Use your admin key. Group and invite actions are rejected by the relay for non-admins.
Rooms on this relay. Create one, then add members or mint an invite.
Add or remove people from a room.
Everyone with access to this relay.
Mint a link that grants relay access and drops the person straight into a room.
For family who can't make their own key. Generates a key, adds them to a room, and gives you a backup + login link to hand over.