**Supposedly** you should be able to invite <20rep users and allow them to chat using this:

> ## Explicit write access add a user

> Even when this room is read-only or **their reputation is too low**, these users will be able to talk in this room.

**But that functionality hasn't worked since a good time.**

![enter image description here][1]


  [1]: https://i.sstatic.net/dCKiJ.png