There is a group campground,down close to the river. We have used it many times. There is a for a couple of small RVs and lots of tent space.
I have camped there and did not see a group camp. All the sites are pretty small.
I have never seen a group campsite there. There is a day use area for a fee, but all of the camp sites are for car camping or RVs. Best of luck to you.
Thanks! Your answer is awaiting moderation.