I have 5 large blue gouramis and 3 dwarf gouramis in the same tank as about 16 tiger barbs and haven't had any problems. As long as you have a bunch of em, I'd say 6+, they won't bother the other fish.
HOWEVER, I am trying to get rid of the barbs. I can't put any fish in the tank that are smaller then twice the size of the barbs, cause then they will cause a problem.