Groups have a personality as well as Individuals
It is important to photograph groups like you would individuals - if it is a formal group
don't have them lounging around a swimming pool - if it's a swim team you might want that
background. Trying to match the background and posing to the nature of the group is
not that hard but it does require a meeting with the photographer prior to the session
so that a suitable location can be found.
Some groups might actually look more natural captured 'in action' rather than posed.
Groups