2-group

A 2-group is like a special club where there are only two types of people allowed in - let's say boys and girls. Boys are in one group and girls are in another, and they can only talk and play with other members of their group. Everyone in the club has to follow the same rules and behave nicely to each other. Sometimes the groups can get together to have fun, but most of the time they stay in their own groups. It's like having two different teams, but they both belong to the same club.