This is what happened between my Abby and Becky. A cat outside really really upset Becky and she turned on Abby. And Becky was really nasty tempered.

The Cats International site talks about this type of redirected aggression:

For example, Cat A may be sitting in a window as an outside cat walks by. Cat B sees the outside cat and rushes toward the window to attack it. Unfortunately, Cat A happens to be in the way and sees Cat B aggressively charging toward it. Cat A puffs up and hisses. Cat B redirects its attention to Cat A and puffs up and hisses. Then the cats attack each other. Each acts as if the other started the fight.
Although this is not exactly what Eddie and Edwina did, I'm sure it's a similar problem. Read here for their suggestions:

http://www.catsinternational.org/art...ther_cats.html

As they suggest: separate them and then reintroduce them. This worked for Becky and Abby. Abby was still nervous, but the hissing growling and glaring stopped.

Then, of course, there's Feliway. Which does help.

Good luck to you all.