For the first week, the groups were kept apart and encouraged to participate in separate team-building events and activities, in order to form relationships within each group. They established their own hierarchy and elected leaders, and gave their groups names -- the Eagles and the Rattlers, because it was the 1950s. Each group even designed flags to represent themselves. Then, once each group had formed a close-knit bond, the Eagles and the Rattlers conveniently "discovered" each other, and both sides approached the situation with about as much grace and understanding as David Duke running a three-legged race with Tyler Perry.
To see how much conflict they could instigate between the two groups, the experimenters arranged a tournament with events like baseball and tug-of-war, promising shiny trophies and pocket knives to the winners, because as we all know, the one prize you should always award a warring band of feral children is a knife. With a little creative prodding, what started with boos and insults quickly escalated into a full-out battle, ending with the Eagles burning the Rattlers' flag after being defeated at tug-of-war.
A nationalistic coup then wracked the Rattlers, leading to the establishment of a military junta.