I just acquired a beautiful trio (1 male 2 females) of pearl gouramis. If I want to add more, would you suggest another trio, or just more females?Normally trios and sixes seem to be the best way to diffuse aggression with gouramis. It may be advisable at this time to add one more or four more to balance things out. For me, six has always been the magic number keeping most of the more common species, like honeys, pearls and moonlights.
On the problem of bullying, it is definitely worth a try to separate the fish for a few weeks. If nothing else, it will let the bullied fish recover and become stronger.