How to Allocate People in a Rooming Group

i was trying to figure out how to alcate roommates in our rooming assignments. i had figured out as an economist that we needed a really big group. But the problem was we didn't really even like each other very much. So i set up a computer programme where each of us will anonymously enter our own preferences about who we like and don't like, and write an algorithm which would do all the calculations for them. As soon as i looked at it, i realized i had made a terrible error in logic. Because what had happened was that it had decided that the most efficient way to alocate people was to put the four people that nobody liked all in the same room