If possible, you could take the divider out and "frost" it. I did that with mine.. used to be clear plastic sheets, then i sanded them down so they were pretty frosty..
If you can't take them out tho.. you could always put some backing paper between so then that way there's definatly no chance they will be able to see each other, cuz once they have caught a glimps of another fighter, they will more than likely keep goin back to the samespot and flaring at each other.. silly fishes ^^
Wish they got on.. community tank with more males would look awesome!!! shame...