The "Registered" users group has permission to start new threads, reply to threads, and view threads in all forums. So in the Classified forum I set the permission to start new threads under the Registered user group to Revoke.
I then created a new user group called "Seller". In the Seller user group permissions, I did not change any of the permissions because (if I understand permissions correctly) that new group will now inherit all of the "Registered" groups permissions. I then created a group promotion (also called "Seller") with the option, must be logged in, belongs to registered user group, and must have 20 posts. Last, I changed the permissions for the Classified forum, under the Seller user group, to allow for the can start new threads option. With all of that, my members still do not have have permission to start new threads even if they meet the criteria of the 20 posts. Also, I assume that the Seller user group automatically gets added as a secondary user group once the 20 posts are met, but when I search for a user that I know has more than 20 posts, there is no secondary user group listed.
So I ask, what am I doing wrong? Or how do I bulk add every member that has over 20 posts to the secondary user group?