notoriously hard to sex....
you may have 3 females yet...
have two paired off? are two defending the eggs from the third?
if im not mistaken the fish will fan the eggs to keep a flo of water around them. water quality is important as some of the eggs will begin to go white (infected) the mother will pick these off to save the others, so now is a good time to add a light dosage of some antibacterial treatment.
if they are on a rock or similar you could lift the eggs and place them behind a divider. you will need an airstone to simulate the mothers fanning. but in a few days you'll know if the are fertilised. if its the first time dont hold your breath some can take ages to learn what to do. or another fish can come in a swipe out the whole lot over night.