Get one of your friends to come with their horse and just practice it over and over and eventually he will get used to it!
Don't avoid head to head contact never! Mine did the same but week after week he's getting better, now he only spooks once or twice ! Just be super cool when he spooks and try not to give too much attention in that moments.
If you have friends that have horses and a place to ride, start out slowly at a walk and have them come toward you. After many passes of not spooking, reward him. Then move the other horses closer and go to a trot, then canter. Make progressions over an appropriate timeline until he is 100% sound. Horse shows will become a breeze! :)