The list shows posts with high pay-out rewards. This doesn’t automatically mean there is a reward circle in place.
There is a circle when you see a pattern of who gets rewarded by whom, how much and for what. This could still be a group of friends rewarding each other, but could also be a user with many alt accounts.
It may be a good idea to check what they are rewarded for. Original content? Or mostly copy paste posts, with just a small alteration?