Wow, thank you Cindy for the really good information. I have been around dogs all my life. My parents always had two or three, and so have we, most of the time, but we've never had this problem before, they always worked things out on their own, we've coexisted fairly harmonously without formal training. It looks like there's a little more to owning multiple Yorkies than I realized. Will definitely have to do my homework.
Will look for a qualified trainer in our area for help. I also have a good friend and work associate in New Jersey who was very involved with training in his area for many years. He alway asks about Zoe when we talk, but haven't spoken with him since this situation developed.
Don't worry, I haven't used the Alpha roll, yet, and won't after reading this.
Now I understand why Zoe gets upset when I roll her on her back to brush her tummy. She probably thinks I'm forcing domination on her.
And I thought parenting was a challenge