I have only two females in a community tank (the most unlikely of tank mates nonetheless). I floated the last female, Jadzia, in the tank for about an hour and the other female, Sita, was able to check her out and flare and do whatever for an hour. Then I placed some of the tank wanter in the cup for her to get used to, every 15 mins for an hour. I allowed them to become acquainted with each other for about 2 hours and then released Jadzia into the tank. They flared for a moment and then all was well.
I don't recommend doing this if they seem aggressive towards each other, because it could possibly end horribly. If they seem fine, then continue with more. Since my community is a settlement of different variety of fish with a lot of hiding spaces and a working pecking order, the two females never fight, it may be their temperament. Most would get angry that I only have two females together, but they're docile towards each other... Also, be sure you have a lot of hiding places for them to swim into, in case they do not get along, at least they could seek refuge somewhere.
This worked for me, but different fish mean different circumstances and different outcomes. Good luck!