One thing you will find about a sorority is that female betta are nearly as aggressive as males and in some cases more. Ive have to house a couple of girls in their own space for the safety of the other girls. There is always fighting over the pecking order. Over time you hope for a balance and less aggression. It can be hard on a fish keeper to watch the bullying at times. It is deeply engrained in the DNA of this species. Get lots of plants in the middle of the tank and many hidy spots. If the fighting gets ridiculous ( life threatening) you have to get them apart and maybe try later. Good luck.
as a matter of fact, you should go into all the topics and read all the threads that are permanently pinned to the top of the forum. They have tons of info for newbs. I found them very helpful and still read them after a year of betta keeping.
Not really a sorority if you have only 2. I just suggest dividing the tank or give them each their own tank. I really recommend 4 females as minimum.. If 3 happens then 2 will gang up on the 3rd one. That's just likely, not always. Once you are able to get more, then it should be fine. Remember to read the sticky, get many decorations, and QT them.