Off the top of my head these are rides/attractions that you can all three ride/do without being split up:
MK- Haunted Mansion, Splash Mountain, Winnie the Pooh, the Ariel ride, Aladdin's Magic Carpets (each carpet holds 4. 2 in front 2 in back), Pirates of Caribbean, Jungle Cruise, Enchanted Tales with Belle, Monsters Inc. Laugh Floor, Tea Cups
Epcot- Soarin, Test Track, Turtle Talk, Seas With Nemo,Living With the Land, Ellen's Energy Adventure, The Three Caballeros ride,
HS- Tower of Terror, Star Tours, The Great Movie ride,
AK- Kilamajaro Safari, Kali River Rapids, Dinosaur, Primeval Whirl, It's Tough to be a Bug
I know I am missing some rides, but those were just off the top of my head. If you look on the Disney website under things to do/attractions tab it should list every ride with details. Also, there are tons of shows that I didn't list where you will all be seated together.
Have fun on your trip!