Any advice on how to get the 2 girls to stop beating the heck out of the boy?

Pacasso is a fearful cat by nature, so he STARES at the girls and they loath it. So they attack him and chase him around every time he does it, which is a lot.

All the kitties have their claws cut weekly to prevent scratching the couches and hurting each other. The girls get a long ok, they are not buddies, but have no issues laying near the other, but nothing closer then a foot. I have never seen the 2 girls fight each other, only growl if the other gets too close. They both seem to respect the other, and they both are trying to get closer to the other so I'm not worried about their relationship at all.

I took away all the free kibble and closed the bathroom door, as that is where the most fights broke out (common meeting area). They all eat in the kitchen a few feet from one another no problem, and all beg for me to hurry up while I prep it. No fighting or hissing ever happens.

I'm pretty sure its the staring that is causing this fighting. As Both girls can walk near him if hes sleeping, and they wont bother him at all.

Any advice?