A method for a computer system includes receiving a first user communication, determining a first group of users, determining a target number of users, determining whether the first group of users includes the target number of users, and if not, providing the communication to the first group of users, determining a hierarchal mapping of groups of users in response to user memberships, determining a second group of users from the hierarchal mapping, determining a plurality of social network relationship factors for the second group of users with respect to the first user, and providing the communication to at least a subset of users in the second group of users in response to the first plurality of social network relationship factors.