My two are like that. One is an inhaler, the other a pick-at-it. With a lot of work - pulling the inhaler away from the other's dish, etc., the rule has finally been established that the inhaler is not allowed to eat the pick-at-its food. Instead, she comes and visits with me until he's finished, then they both race outside.
I haven't found anything that slows her down with her eating. I do make them both wait until I set the bowls down and say "OK" before they can start eating. This keeps her from jumping on me trying to get to the food faster. I do the same with treats and toys. They have to sit and wait until I say OK - then they can have it.
I do have single step stools where I place their food bowls - it raises the bowls so they don't have to bend their necks down as far. I don't know if it REALLY helps prevent bloat, but it was cheap enough to try. The rocks in the bowls, etc. don't seem to slow her down at all, so I don't bother.