It is never a good idea to keep snakes together. One, if someone gets sick, they both have to go to the vet, either because you can't tell who regurged/had bad poop or because the second snake has been exposed to the sick one. Also, cases of cannibalism have been reported. Then again, there is the stress/competition issue. Stress from competing for the best hide spots, the best hot or cold spots. Stress can lead to illness and nonfeeding.