You can ask that two reservations be linked, but it will be treated as a request and won't be guaranteed. Ask when the reservatino is made and again at check-in. You will at least still have to re-check-in and get new room keys for each reservation change.
If you reserve any cash nights thru DVC/MS, they will be linked and you will NOT have to move, but booking thru CRO involves a different reservation system.