What you want is a non-persistent or "Floating" pool. Then you can have several users on the same desktop (but on different times)
Just choose that option when you create a new pool.
Users will receive desktops picked randomly from the pool each time they log in if I go with the floating pool route.
I don't think their user profile will follow them to the next desktop will it?
I just created a Floating pool as a test but I had always wanted the user to get the same desktop on every login
You could create several floating pools with one desktop in each, then you can achieve the same functionality.