Welcome Nancy!
Hooray for planning your magical vacation with friends or family. Selecting MagicBand colors is always an important step in our vacation countdown, although, it's hard to choose which one.
You should be able to add the second reservation number to your My Disney Experience account, however, if your name is not also on that reservation, you may have some trouble. If you've already tried to
"Link Your Resort Reservation" with the additional confirmation number, you may have to
call and speak to the My Disney Experience account online help desk, to see if they are able to attach your account to the reservation. I had to do just that a couple of years ago when I was planning a stay for my family and my brother's.
As far as adjoining rooms, I prefer to call Disney Reservations and ask the Cast Member to link the two reservations and make the request for adjoining rooms. While they will do their best to accommodate your request when it comes time to assign rooms, please be aware they are not able to guarantee it. You'll find the number for Disney Reservations through the above link as well.
Happy planning, Nancy, and please let us know if there is anything else we are able to assist you with.
Pixie Dust,
Lauren