a little more info please,
what type of tank, what size, do you have live plants or fake and how many and any caves?
secondly, in order for female betta to be kept peacefully together you need a minimum of 4 girls and a tank that is 10 gallons or larger with lots of plants/caves hiding holes and whatnot. if you have 2 girls they will fight until one dies in most cases, if you have 3, it is very likley that 2 will gang up on one and kill it then fight each other. females always establish dominance and pecking order amongst themselves. i have 5 girls and a bristlenose pleco in a 30 gallon but if it were just the 5 girls i could get away with a 10 - 15 gallon aquarium (bn plecos produce ALOT of waste and get around 4-5 in long so they require large tanks)