Pretty sure the 'groups' camp fees exceed yours, so.. If you leave they still make more money than you just leaving... Even if they give you a refund, which you should totally ask for..
It's not right by any means... Just sounds like a place that has so called 'rules', but if you have a group that is probably paying a lot more to be idiots, then what can you do..
It's a private business on private property, so calling the cops is not going to do anything either.
Tough deal for sure.. I've been burned by a hotel chain to accommodate a large group and basically said my reservations were cancelled on the day I arrived... They gave me an alternative option of $50, which I took, but that only paid for dinner that night for 2 of us, but we did find a much better place to stay in the end, so whatever..
Good luck! Mitch