Hello Janine! Welcome back to the Disney Parks Mom´s Panel.
How awesome to experience a Walt Disney World vacation with friends. It is a great decision to start planning your vacation early, especially for a December vacation.
For my family´s 2013 Disney vacation I have already booked a few Advance Dining Reservations that include my brother and his family. We are a family of four, so is my brother´s family, and I had no problem booking a reservation for eight. Still, I did not link this reservation to my resort reservation or dining plan.
During our 2012 Disney vacation we did booked Advance Dining Reservations for eight guests and did linked these reservations to our resort reservation and our Disney Dining Plan (the other four did not used dining plans). At the time of ordering we did tell the waiter who was and was not using Disney´s Dining Plans. I would expect this to still be possible.
The other guests will be able to view all dining reservation with the
Family & Friends tool in My Disney Experience.
Remember that you can also book Advance Dining Reservations by calling (407) 939-3463.
Happy to help you plan a magical Disney vacation.
Miguel