If your dog has a dislike for someone, why waste your money using that person to handle your dog? Or risk making the behavior more common by it being repeated.
That said, you can in fact work on the "approaching" issue. Take your dog to a show he's not actually doing, or a human park that allows dogs. Get a helped to ask people to walk close by, but no closer than about 5 feet, and toss a small treat. Once your dog is happily anticipating the approach. .. go home. Next time have them come withing a couple of feet and drop the treat. Next time, have them squat down with hand out with treat. Next outing, try to allow to smell and lightly pet shoulder area then move on. Don't force any contact. If the dog dislikes some folks, try to figure out what the common issue might be. If you can figure it out, break out the fantastic treats and get people (for example, could be hats, perfume, flappy shirts…whatever) with that to come. It helps if your dog is HUNGRY prior to the training. It is a bit of a pain, but a dog who shows aggression or fear in the ring is not going to have a very successful time. In fact you risk being banned.
If you can't fix it with the above, it may be time to call in a good, positive trainer to evaluate. Because if you simply have a dog that is fearful/aggressive that cannot be overcome, you might want to seriously question whether this dog should be show or bred.