Poor Joey

I guess it's a couple of weeks of worrying about cats. This morning Kit Kat got in a fight with Joey...I mean a full on fight. Tuffs of fur everywhere. We had to literally separate them! And all Joey was doing was using the litter box. So Joey has been under our bed all day. We were playing with the red light that Joey especially loves and we could barely get him to cross the threshold between our room and the living room! He was that terrified! He has a scratch on his nose and it looks like there is one on his ear. Over the last few weeks Kit Kat has been getting more aggressive and Joey is especially afraid of him...most of the time he stays in our room and anytime he even sees Kit Kat he runs. Joey usually is a really happy cat and it's really killing me to see how scared and unhappy is. We're getting to a crossroads with Kit Kat. He really is a sweet cat IF he's the ONLY cat...but he's just not meshing with our cats well. I'm not one to just give a cat away. But I don't know how much more I can put my other cats through.