Several years ago my dogs were barking at the cars and people in the parking lot behind my house. At the time all I had was a chain link fence. As a temporary measure, I attached several sheets of thin, cheap plywood to the wire fence. It kept the dogs from seeing the people, thus cutting the barking down some. Now I have a wooden fence and the dogs are satisfied that they don't have to "save" me. Maybe you could try using cardboard just to see if that could work. If it does, then go to something more attractive.