
It would be worth contacting some training club organisers/trainers to find out if this is possible in your area, they may know of an e4xperienced owner with a very steady non confrontational but confident dog to walk with.
I took my friends Goldie who was like this out with my dogs for years (she can't manage now at 10 as in her head she is Peter Pan, but her bones are old). She used to hate other dogs but gradually with me being careful, but positive, and her seeing how my dogs interacted, she is now a confident soul, (took about a year, but was much better within a very short time, as she knew this behaviour earned her nothing but my disapproval), no longer feels the need to defend her self in an extreme fashion, and that sexy males should be shown disaproval, but not be killed outright! :D
I would suggest a training class as a first step. Just sit near other dogs, and make it clear that good manners are expected, b ut sit a distance from other dogs that he/she feels comfortable, and gradually reduce this with the most friendly and reliable dogs.
My friend (an experienced Obedience handler, who competed up to Ch Class C in her younger days) often has such cases to her advanced class (mostly her cronies who come to practice), as the owners are experienced dog handlers! We have had great results with a 12 year old cross, whose lady owner is terrified of big dogs, and had made him that way. Her Dad decided to bring him, he doesn't want to play with the other dogs, and does tell them off in a mild way to leave him be, but he tolerates them now. Similar situation with a Jack Russel, tends to grumble a bit6 if they get too close to him, they takle the hint, and he doesn't loose his rag any more (he knows his owner will not tolerate bad manners from him).
I would enlist other dog owners who you feel have the type of dog and experience, tyhe trainers may know or be willing!