To be brief: I would really just get a separate enclosure. There are rare instances of corn snakes eating other corns. It's not expensive to house a corn snake, and the adult corn may really stress out the younger. It just seems like a really unreasonable thing to do. I would never put another corn in with my girl for any purposes other than breeding.
If you're worried, why even consider doing it? There are 0 benefits for the snakes.