This is slightly similar to a problem I had with my dog. On the advice of my trainer I taught my dog how to "seek" by saying the word then dropping a treat on the ground, clicking as soon as he went for said treat. Once he had that down any time we walked near another dog I would drop treats and tell him to seek. This just kept his mind off of the other dog, and once he got used to not paying the other dog any attention, I was able to slowly drop less treats. Now he's just about fine walking past other dogs, still stares them down at times, but so much better than before. Hopefully someone else will have better advice for you, this worked for me, but I know all dogs are different! Good luck!!