Email-only discussion groups for hosts

Is anyone aware of good email-only discussion groups for hosts of short-term rentals? Their content would not be published and searchable publicly. Instead, it would be accessed only by the authorized members of the discussion group privately - by receiving all messages via email or by logging in with credentials to view them.

You could set up a private FB group if one doesn’t already exist.

This is in general hard to guarantee on the net. Anyone could put the contents on a mailing list online - it would be hard to stop unless the group as a whole had some leverage over the individual members.