Patent ID: 8238282

Claim:
A network system comprising: a plurality of M terminals each connected to the network, wherein a certain one of the M terminals comprises: a terminal memory for storing relationship information about the M terminals whereby each of the M terminals is associated with one of N groups where (N<M); a receiver for receiving at least one first information from a different terminal; a generation component for generating second information from the at least one first information; a group selection component for determining a group associated with the different terminal and for selecting a group, to which second information is to be transmitted, out of the N groups on the basis of the relationship information and the group associated with the different terminal; a terminal selector for selecting a terminal, to which the second information is to be transmitted, out of the terminals associated with the selected group based on the relationship information; and a transmitter for transmitting the second information to the selected terminal; and an administrative server connected to the network, wherein the administrative server comprises: server memory for storing server information about the M terminals whereby the M terminals are associated with N groups from the view point of each of the terminals, wherein the server memory in the administrative server stores server information about the M terminals in a data structure of a tree structure configured of leaves associated with the respective M terminals, and stores the server information about the M terminals in a manner that the M terminals are associated with the N groups having the hierarchy structure according to hierarchy levels of nodes each shared with each of the leaves of the tree structure; and server transmitter for transmitting to each of the M terminals relationship information on the relationship in which the M terminals are respectively associated with the N groups, and in the certain terminal, the receiver receives the relationship information on a relationship in which the M terminals are respectively associated with the N groups, and the terminal memory stores relationship information about the M terminals in association with the N groups.