Champ,
Compotent training for formation flying is vital for safety. I must not be caually undertaken, and ATC must be notified. They will generally handle the group of aircraft as one to the greatest extent possible.
Multiple aircraft on the runway is extra dangerous, and requires excellent pilot disipline and skill. Training and practice!
Do not go formation flying (within 250 feet of each other) with your buddies until until you've got the training, and the aircraft owner's permission. Many owners will not permit it, and you don't want to be on the wrong side of the insurance company either....
Fly safe, Pilot DAR