If you'd like to start a proper sorority, invest in a 10gallon and cycle it. (cycling is good for the tank & helps keeps water params stable) && at least keep the 3 gallon heavily planted so that their line of sight is broken. If you can, get 3 separate 1gal tanks & separate them until the 10gal is cycled.
Heavily plant/decorate the 10gallon and leave some hidey holes for the female to hide in. The fishes line of sight should be broken so that a chase/fighting can be minimized for the girl who is trying to get away. :) you'd also need a few more girls. But, that just means more fishes! :D