You would have to book the room together as one bid or one buy first of all to be sure you even have the same hotel. Then your chances of getting joining rooms would be the same as if you booked with the hotel directly, if they have it, they would give it. After you win your bid, wait about 2 days then contact the hotel directly to request it. Remember, it is only a request and not a guarantee... as with any hotel. I have even seen Disney not follow thru on its requests at times...
The one important thing you must do though is book the 2 rooms as one bid... or you might not even be at the same hotel....