I have had 2 young geldings raised by stallions come to me to be started. The first, had a tough horse mom that facilitated ground manners. He was a breeze. The second, was raised by an old stallion he could push around. He was a heathen, and tried to run at me and attack me and knock me down multiple times when i was first starting him.
So for the sake of safety, put him in whatever group that will kindly teach him respect. That might mean he is the last to get shelter during a cold wet rain or the last to eat hay on the roundbale, but it will surely keep the humans safer when its time to start him.
I as the human would be doing some dominant groundwork with him too - just so he learns to respect hunans because I cant imagine him playing that rough and not being a pill on the ground.
He sounds like he is also very dangerously kicking. Have you messed with his leg and made him wear polos etc yet? Geldings can be so weird and throw monster spooks when stuff touches their legs. The older i get the less tolerant i am of bad behavior so i have never done this before but if his kicking contines i would put a homemade kicking chain on with a dog collar around the hock and let that hit him when he kicks and then it will be like an act of god and he will stop. I mean, he needs to learn it is wrong before people and animals get hurt.
Maybe I just spend too much time training rank youngsters but safety of other horses and people should be the primary concern .
Lastly my youngsters always play with the older horses when they are in the mood. Yesterday I watched them play rear and chase with a goofy 7 year old gelding - it was fun and respectful and nobody got hurt.