Groups of 3 and more can work where they've got plenty of space to escape any bullying or mating activity... well done
It's entirely typical that they all want the same sunbathing spot! Keep an eye on them and be prepared to split if one starts to be come withdrawn or the battles for the best bit start to get nasty!
My Russian bullies the little tortoise statue I put in her cage. She sometimes catches sight of it across the cage and does the head bobbing. Yesterday she was biting it. I believe the statue is withdrawn because it doesn't eat.
What's weird is I see her looking into Henry's cage but she never seems to want to get in there and I never see the head bobbing in his direction. Maybe she is thinking to herself.. as long as he stays over there... I will hold off on beating him down..