i recently put my girls in a sorority tank and ended up doing a lot of research and this seems to be the general rule of thumb....
1. no less than 10 gallons
2. LOTS of hiding places
3. no less than 4 females together, if you have 2, they will fight, if you have 3, then 2 will gang up on 1 (then you still might end up with 2 fighting in the end)
4.some females are too agressive and it wont work but it most definatley can be done with the proper set up, they will establish a pecking order so a small amount of fighting in the begenning is fine, i just watch very carefully to make sure it does not go too far.
I have 1 wh o was more agressive at first and she ripped most of the ventral fin and the upper lip off of my ct i had just gotten for my first breeding (in like 5 weeks it will be breeding time... i might not use her now) but the ct ripped some finnage off my agresive one and they have not fought since that first day, none of the other fish fought so i dont know if i was lucky to get ones that can get along or if thats normal. i have 4 girls in a 30 gallon tank with 2 big caves and a couple other hidey holes along with a large plant, a ping pong ball and a floating plant thing... hoping to add a couple more big plants...