You might be able to get away with it, but why risk it? If anything they'd be more likely to prey upon each other while they are small. I have one female pigmy rattlesnake that has killed 2 males. I have other adult rattlesnakes that I house together a large part of the time.

Interesting technique... Most people I know that breed snakes put their snakes together for breeding rather than separate them. Snakes breeding while separated must be quite interesting.