You can only keep the females together and even then there may be some bickering between them. The best thing to do would to put many plants or hiding places for any fish that may be getting bullied too much. It will allow them to get out of sight, but if the fighting progresses the betta or bettas should be removed immediately. Sometimes it works sometimes it doesn't so be prepared. Some females tend to be bossy or docile it just depends.
As for the males, I wouldn't even think about trying it. I can easily guarantee that if you put the males together you will end up with dead fish. Please keep the males separate, and watch the females.
As for the males, I wouldn't even think about trying it. I can easily guarantee that if you put the males together you will end up with dead fish. Please keep the males separate, and watch the females.