Moonshae, I think I will just have each group of kids make their share of the "community" root beer and pour into a corny keg. The logistics of force carbing 25-30 bottles with a carbonator is just too much work. So, I will force carb in the keg and use BierMuncher's DIY bottle filler to fill the 2-L bottles.
Thanks to all of you for your encouraging words and advice. I will let you know how it goes.