On Facebook I have started and I belong to different groups - now GROUPS are different than pages - some of these groups are open to anyone - and I recently started a special one for a class I took part in on line - now this group is closed and SECRET  - and you must be a member of the group to see it and post in it -  
 
I could set a similar thing up for GCU - once it is set up anyone that wants to join would have to message the other members of the group (there would be no in charge person) any member can invite or add someone to the group - but it would be a secret group meaning that no one outside of the forum/artists on GCU that know about would be able to stumble across it - so artists could post pictures of WIP cards, or ideas for verse and help each other out -  
 
You must have a facebook personal page and if I was to add people they have to be on my friends list - ( haven't found a work around for that) BUT I do have a FB profile just for my store - https://www.facebook.com/SerenityShoppeCard
 
Patti