[horsnaround]

I hope you get it figured out. My daughters two dogs started this after one was three and one was six It got so bad they were actually hurting each other. We tried everything one was neutered and one was not. Neutered the one hoping that would work. But it didn't. I think we tried everything. The vet suggested. We tried scents we tried a mild drug we tried the attention thing. Like you we feel are dogs listen well and are very trainable. Needless to say I took one of them. They get along well with all the other dogs just not each other. To this day when my daughter comes to visit we have to take turns with them running with the others. The minute they get to close to each other they start growling. And it's been 3 years since they have lived together I do not understand it at all. We have dealt with two different vets on the matter. Besides reading everything we could and then trying it. We have accepted it and keep them apart. I sure hope Mylee and Moka do not get to that point. But when our two fought someone and usually both were bleeding that's how bad it got. Sorry I have no good advice.
We have the occasional bullying around here with the three of them but nothing even close to how the two would go at it. And usually a stern voice they will knock it off And never bite are draw blood. Good luck and keep us posted on how there doing and any tricks you learn along the way.