You could of course Paul, once you get breeding them, use only males in the tank.
The males will "flash" to the others.
The best tank I ever saw of killies was an all male gardneri blue, in a river bio-type.
I wouldn't agree with the australe.
But what Shae says about the cross-breeding is correct with the three named gardneri.
Don't keep any babies if you do mix them.
In other words DON'T pick eggs, and the adults should take care of any babies that do appear.
The albinoes are really special, and I know that at least twice, they have been down to almost impossible numbers, but have then been bred up and got out to the members again.
It is so difficult to get new fish, that "we" try to keep them as pure as possible.
Take care of what we have, we may not be able to replace them.
Alan
NZKA 104