I am in the same situation actually, the people across from me Husky goes after the German Shepherd every time my boy and I walk outside. I spoke to the women, and she is convinced they are "playing" and I just do not know them. Called Animal control and they could not do anything about it since they are in their own yard and the owner thinks they are playing and suggested maybe I try not to leave when I see them in their yard.... I would try and take a video of it on your phone to show the owners, I say try speaking with them. You could say you are not familiar with their dogs but you just want to make them aware of what happens when another dog passes. Nothing happened as a result of me speaking to her and I try not to leave on walks when I see them outside. Sucks, but what can ya do... I feel my chance is gone, but if you go with a video of it they may be willing to watch and listen to your concern.