Non-circular boring. (Linuxcnc fun)

would you be interested in creating a custom program for a mill to machine some trapazodial pockets on the ID of a round part? it's either that or I am shaping in the lathe, just curious if you think this is possible, the pockets are only 3 side, the back side is open to the ID of the part, it's a transmission clutch drum

Could you share your complete setup for doing that type of work on the lathe?