Hey, we live in Haverhill too!!! Flynn has similar issues with dogs (on leash), if he can't meet another dog, he starts barking and whining. We've been having him sit and focus on us during walks when other dogs are around. We go down to the Cape on weekends in the summer, and bring Flynn to the beach. We are still working on redirecting him by bringing him to the water to swim or by playing Frisbee on a long leash. Flynn is 2 years old, so we think he'll get the hang of it pretty soon. He has a thing about small dogs or black dogs, particularly GSDs, doesn't like them at all, but we can get him to sit and focus on us, or tell him "quiet". Good luck--and it would be fun to meet up with you sometime.
Cassie and Flynn