Cat's Meow: Fighting

We knew introducing a new cat into our home would be a serious transition for our first two furbabies. We just weren't sure how long the transition period would be. Well, nearly 6 months later, they still aren't getting along, as evidenced by recent scratch that appeared on Callie's nose.

We're not sure when it happened, or who caused it, but we assume it was Cruz. He's usually the instigator. And he's the one that Callie has had a tougher time warming up to. She and Periwinkle tolerate each other, but they still have their moments. 

We're still waiting for the day that all three of them will get along. Glimpses of that life happen on rare occasions, like when we treat them to wet food.

But we're keeping our fingers crossed that that day will come sooner rather than later...

Any suggestions for helping cats get along? We've tried nearly everything we can think of, so any ideas are welcome!