Hi, I also have siblings that are litter mates, and they can get rough sometimes when playing, I generally will let them play together, as long as its not too rough and they're not hurting each other, but I will usually either separate them if I see that they are getting overly exerted or overheated, and definitely if they are panting really hard or breathing is too fast. They will sometimes just stop on their own and lay down on the floor and rest, but if they don't, I can usually tell them in a firm voice that's enough, go lay down and they will stop. The odd time if they don't, then I will separate them, and crate them until they settle down. I would definitely separate and crate them if it was 12:30 in the morning, and they were still playing hard. They should be tired out at this point and should go to sleep.