You can request rooms beside one another but from experience the hotel doesn't act on anything until you check in so ask at check-in and if they can they will accommodate your request. I have had no problem in this regard. It will also depend on the type of rooms you have booked. A "junior" suite may not be next to a regular room.

You can have your travel agent set it up, call the hotel ahead of time, or ask upon check in. They will always put you side by side if possible.

Email them and hope for the best. They won't guarantee your request, but will try their best to horror it.