Patent attributes
A relay server stores registered terminal information and information about the relay servers that form a relay group permitting connection among each other, about a shared resource, about terminals sharing the resource, and about a message to be transmitted in association with the resource. When an operation instruction regarding the resource held by another terminal is received from the registered terminal to which the relay server is connected, the relay server relays the operation instruction to another relay server. When the message is transmitted to the other terminal by the terminal, message information is relayed.