Maybe baby gates could be used to keep the girls separated at times? Let your yorkie play with the male, whom she gets along with, and rotate the females in and out until you can get a handle on this.
My male Westie ONLY gets along with females; he is very territorial with any other male so we knew our second dog had to be female. Even then, it took some effort on our part to facilitate their relationship.
When Ringo got jealous of Lucy (he didn't like her on my lap or on the furniture at first); he got to spend some time alone in another room if he showed aggression to her. He figured it out real quickly ~ as long as everyone is playing and getting along, we all get to be together. If he got out of hand - he went into another room. I didn't use his crate much for punishment.
Same with Lucy; she can be all over Ringo trying to bite his paws, etc when she is feeling frisky. Then she might get to spend some time in the living room while Ringo gets some extra human attention.
It took us about a month to get everyone settled down. Now they are fine; sleep together on the same bed; but they occasionally will squabble over high value bones, etc. We feed them separately and walk them together often.
Best of luck.
__________________  Mommy to Lucy, Ringo, and Matthew |