Louise, we have been fortunate. We do have two family dogs that have problems. But, it's over food. As long as we are aware and don't let them around the food together we are fine.
My Jack Russell can be a little protective. But, it's been good for her to be around the other dogs in the family. Today, I had my sister's dog for the day. She outweighs Misha by 60 lbs. I've seen their interactions and know that Misha has learned boundaries by being around this dog regularly. They get along really well. In fact, they spent Thanksgiving together at my sister's and I did not have to worry about either. My sister's dog is one of the ones that has problems when food is out, however, she doesn't seem to be bothered by Misha in the same situations.
She does, however, play with her a little too hard. Because Misha doesn't have any doggy siblings, sometimes she is scared by it. My sister's dog thinks she's like their cat and will run around. Misha just stands in place and panics. LOL Other than that, they get along fine.