Does he only act this way when another horse/rider run past or does he also object if they walk past? Just curious. Agree with Painted Horse. Put his butt to work. This will be easier to work on when it's just your family riding and not a group ride.
Bellasmom has a good point. Running past other riders is rude, and a bit dangerous. If riders want to step it up they should be off by themselves or ride with others who enjoy the same activity. Nothing wrong with speed. Ask an endurance rider. But most group rides is not the place. Still, your horse needs to stop his jumping around.
If you ever find yourself in a fair fight, it's because your tactics suck. ~ Marine 1SGT J. Reifinger