Well, I can't speak for Katie's club since I don't know how they opereate.  I know that in Florida these types of "organizations" are gaining speed (althouth they call them escort co-ops lol).  

Basically, the indys pay a set amount per call to the "house" (I believe it's $40.00 or so)for every call booked by the co-op. They pool it together to pay a phone girl/screener, both group advertising and individual ads on Eros and other venues.  The phone girl is also responsible for making announcement/schedule posts on the local boards.

They are indy but don't want to deal with the hassle of screening, organizing their schedule and also get called in and called out.  The only problem that I had with our local co-ops down there is that I have no control over client info (how do I know what they are keeping etc) and that the phone girl is sometimes a retired escort or sometimes a friend of an escort ( no way I am trusting someone that I don't know to do my screening and trust them to do the right thing with info that they may receive. Not to mention trusting an unknown individual with your advertising money, phones and basically your entire business is just crazy).

It seems to be gaining much popularity.  Some gals, like me, would rather just hire a full time assistant or deal directly with the gents. It makes things a little more comfortable for me when I get to communicate with them myself via email or phone before we meet.  Too each their own.  Some ladies rave about it and it works very well for them.
Happy hobbying guys