A method of communication among a plurality of terminals, including transmitting, by a first terminal of the plurality of terminals, a call setup request message of the first terminal to at least one other terminal of the plurality of terminals; and establishing, by the first terminal, a session with the at least one other terminal, the at least one other terminal having received the call setup request message of the first terminal, wherein a terminal having a floor of the session is determined based on priority information regarding terminals that requested the floor from among the plurality of terminals.