you never know you might be lucky and get all 4 fem, why dont you pot them up in soil/ coco until they show sex, dispose of any males and use the females as mothers so you can clone them and put the rooted clones in the hydro system. Or if you dont want to be running veg and flower set ups take the females and rinse the coco off and put them into your hydro set up. Been along time since i did hydro but i imagine its alot easier to wash coco from roots and proceed into hydro than it is to seperate roots from each already in hydro.
I know using coco would mean an extra nute for coco but its a few quid for the A+B needed. Better to spend a couple of quid(£7.50) than to ruin already flowering females by pulling appart the roots.