Classes would help meanwhile, keep a collar or harness on them and when someone comes, hook up a leash. When the start barking at the person, turn them around and walk them away. Wait a minute and then go back. If they bark repeat. Our dachshund got out of control and I started this. If DH was here I let him deal with whoever stopped. If I was by myself, after two tries and she doesn't behave, she is put in a bedroom. When she took the puppy classes, she didn't bark at people at the door. They tried to get her to bark but all she would do is look at the door and then at me. My son's dog taught her to bark at people when we were at the cottage after the classes were done. Think I'm taking her back this winter for training.