Please provide more detail of what you want to do.
If you are talking about Galacticraft's own custom oregen, it is already under your full control surely?
Because there is no option yet to disable Galacticraft ores on Mars or on the Asteroids i thought maybe custom ore gen can do this. I try it and disable some Ores on Mars but it didn't work.
A config file to disables ores would be the better way i think.