A management server issues a game link identifier associated with friend network identification information corresponding to an inviting game and sends the game link identifier to a terminal apparatus corresponding to the friend network identification information. In the terminal apparatus, the game link identifier is passed from the inviting game to an invited game, and the program of the invited game sends the passed game link identifier and identification information of an inviting user, corresponding to the invited game, to the management server. The management server searches already issued game link identifiers, and, when a game link identifier that matches the received game link identifier is found, associates friend network identification information corresponding to the invited game associated with the received game link identifier, with the friend network identification information corresponding to the inviting game associated with the issued game link identifier.