[FirstYorkie]

Just be sure that everytime that bell rings (even if it's just accidentally bumped), you RUN to open the door. Everytime you open that door - even if a dog isn't "asking" to go out - jingle the bell first. You want the dogs to associate bell ringing with door opening.

[Just thinking out loud here. I've never made my dogs ring the bells. I've just made sure that the bell jingled loudly every time the door opened and they've all caught on quickly. I'm wondering if perhaps making them ring it slows down the process? Perhaps then it becomes a command to follow only when Mom or Dad gives the command? Of course, this doesn't help you. Once you've started this way, I'm not sure that I would stop. Just thinking...]