How large is your tank? Dwarf males
can be kept together as well as at least 4 (in your case) females. However, that requires at least a 40 gallon tank. Also, how many platies and mollies do you have and what sexes? As you may have discovered, these breed like rabbits (well, actually, more like
guppies 
) and they can overrun your tank easily. Mollies don't tend to like gouramies much either.
Also, you should know that dwarfs are one of the most fragile of the common gouramies and often carry disease. Stress almost inevitably leads to death - so don't attempt to breed before you know exactly what you're doing or you'll literally kill them. You can't just breed them by putting them together - you need a seperate cycled breeding tank with a sponge filter, heater and a few plants. You also need to have food for the fry - they are tiny and infusoria and later baby brine shrimp, vinegar eels or microworm. You can also buy commercial liquid fry foods but these can be even more messy than the afformentioned live foods. The parents need to be conditioned on live and frozen foods and they need to be seperated for a while before spawning as, usually, they will refuse to spawn otherwise. If you have a spawning tank set up, that's relatively simple - you move the male in first. Also, they have huge spawns - where will you raise the fry and how will you get rid of them? Will an LFS take them? Do you have a grow-out tank?
The reason female dwarfs are difficult to find is that they are not as colorful as males and therefore do not sell particularly well so LFSs don't stock them if they can help it. This is also why many LFSs sell dwarfs as pairs - to ensure they sell the females as well.
Before you decide to spawn this species, try searching this section for threads on gourami breeding. Most of the more common species (three-spots, honeys, pearls etc) have almost identical requirements and breeding habits.
