This is a small usergroup of only 5 with 2 admins so I could do it per user.
Explanation: This is a staff group. But they keep doing far too much support work in Conversations and not using the forums.
At the moment I have had to disable Conversations for everyone
So I want this staff group to be able to contact each other, or Admins.
But they cannot contact anyone else.
No one else can contact them.