when you keep two together, they might start fighting.

basically, one of the snake starts harassing the other snake 24/7, so that the other snake gives in and gets away. well, thats what happens in nature, one would give in and get away. when you keep two in one enclosure, thats obviously not possible, so when they start fighting, it will continue indefinitely until the stress starts impacting the health and one of them ends up dead. snakes are not that smart, and when one snake wants another snake gone, and the other snake doesnt leave, they think they need to escalate it and be even more agressive, because the other snake is being defiant by refusing to leave. they dont make the connection that the other snake physically cannot leave.

nature is big, there is always another rhodent burrow or termite mound, and in nature they would never harass each other for months until the health of one of them slowly deteriorates to the point of death.

that being said, its possible to keep them in groups. its just really, really difficult and advanced stuff. basically when you keep two together, they need A LOT more space and hiding places, so that one can get away from the other and they dont constantly run into each other. maybe 5 times the space that one BP needs would be a starting point, if you want to keep two together. and you need to watch their behavior and be ready to immediately seperate them if things go south, and you also need to seperate them for feeding. so its not a way to save any space, quite the opposite, if you want to keep two together, you need one really big and well-designed enclosure for your experiment, and one backup enclosure for an individual BP needs to be ready, in case the experiment fails.