Hi Lindsay,
Great question! I, too, was disappointed that the rooms weren't intermixed at Art of Animation.
Your best bet would be to book a Family Suite at
All-Star Music Resort and a Preferred regular room there as well. The Preferred rooms are regular hotel rooms with 2 double beds. They are "Preferred" because of how closely they are located to the pool and food court. There are a few things you need to note:
1) The Family Suites at All-Star Music are located in buildings 10 (Calyspo) and 2 (Jazz).
2) The Preferred rooms are located in the Calypso buildings (10 and 1). Therefore, the grandparents room will automatically be in a Calypso building and they'd want to request building 10. For the Family Suite, you'd want to specifically request to be in Calypso building 10 near your other party. If you book both of the rooms together, it will be noted that you are traveling together.
3) Disney does their best to accommodate requests, but they are never guaranteed. To increase your chances of being near each other, you'll want to call the resort directly at (407) 939-6000 exactly 8 days prior to your arrival and ask to speak with the "Room Assigner". Have both confirmation numbers handy and request that you be in the same building. I would also call again first thing on the morning of your arrival and reiterate your request again.
Wishing you a wonderful vacation! Please let me know if you need any clarification or if I can assist you further,
Kaylene