Have the Uaru paired off? They can be rough on each other if they are courting or paired. I have three female severums in my 210 gallon and they are all trying to murder one another over one male. My guess is that's the cause of your Uaru aggression. Otherwise they tend to be good in groups of six or more, very similar to discus and angels.
My suggestion is to watch for the pair (the two that don't attack each other) and remove the others. Are they aggressive toward your discus or geos?
Also, tank size would help. It does look pretty heavily stocked.