How can I separate the wheel hubs from the drums?

The proper way to remove the drum that is pressed onto the studs is to use a "swedge" tool. It's like a hollow drill bit that goes around the stud and cuts away the material holding the drum to the stud. Good luck finding the tool. I was lucky enough to find one at an old Chrysler dealership back in the late 80's that let me borrow theirs. Heating, beating and pressing will only cause damage to the drum or hub.