Keeping large cichlids together

Question
I have a 105 gallon aquarium. It is cycled, all water parameters are fine. I want to put my oscar(12"), two severums(7") and two tinfoil barbs(8")in together but they all,except for the barbs, fight. I removed them all ,except for the barbs, into separate tanks. Is there anything I can do to lessen the fighting such as adding more of one particular fish or arranging the tank differently? One of the severums was picked on so much he had to hide between the heater and filter intake. The barbs were chased by the oscar and kept running into the top of the tank and the sides. Is this hopless or is there any solution to keeping any of these fish together?
Thanks for any help!
Susie

Answer
Hi Susie;

Sounds like exceptionally aggressive fish, even for their type. You can add rock caves to tanks with fish like that but it may not work if they are persistent. You might want to ask Ron Coleman about it. He's very experienced with cichlids like oscars and other large guys. He may have some other suggestions for you. Here is his profile page;

http://www.allexperts.com/displayExpert.asp?Expert=21527

At Your Service;
Chris Robbins