As the sole owner of a gaited horse in my current trail riding "band", I can say it's a bit tricky at first
If the person on the gaited horse is willing, they CAN keep a horse reined in and at a more steady walk, it's possible with seat cues. That method does however tend to annoy my mare for too long, so sometimes I'll let her walk at her breakneck pace to get it out of her system, and then we rejoin the other non-gaited riders
My second horse is an appy/paint, she has a slow as snail pace... but with a little conditioning we are training her to walk a little faster, and keeping Indie a little slower so we can walk together. It just takes a little time and effort and even then not all horses respond to it.