Can I stop dominating Discus from stressing & killing ot

[Plats]

I'm looking for ideas on how I can stop the dominate 3-4 Discus I have, from bullying the other 4. They share a 4ftx18x18 commuinty tank with some thin Val to help separate the tank. I find that after a couple of months a weaker fish slowly reduces it's feeding, then darkens, then it's a fight to keep it alive. Temp constant at 28C
Any thoughts?

[Merrilyn]

Is there a big size difference between all the fish.

Sometimes you just have to separate the bully and give the others a chance to catch up. With seven or 8 fish in a four foot tank, I'm surprised you have aggression. A pic might be helpful.

[Plats]

There are roughly to size groupings. The larger ones are juviniles that have spawned in the tank and then the other 4 are small. The bullying occurs in both sizes trying to get prime positions near the fron tof the tank . You can see the two prime males facing off at each other, in order to get closer to the females on the right. :D