I'll say it...
I'm a pitbull when I race and don't put up with much. I would be scared for another rider's safety if we were in the same field and he was being a jit bag - I have given guys warnings in the past - told a guy last year that I was going to put him into someone's front porch if he kept his crap up. Remember it's not only my size but experience that you must factor in.
Not sure of the best way to do it but new racers, regardless of age should be racing with the 5's.