Looking to get some advice on community relays. 
I'm a programmer and sometimes-sysadmin, I self-host lots of stuff, including a basic personal strfry relay. Even so, the options and breadth of documentation for community relays has been scaring me off doing what I want, which is the following for a few different communities; a relay which can....:

- only allow a whitelist of npubs to post to it
- readable publicly (not whitelisted).
- **provide private (to the whitelist) group chats**. Bonus points if members can arbitrarily make their own groups
- wide NIP support 

Anyone have suggestions for relay implementations and/or guides and docs?
Thanks! #askNostr #relays