Group communication system and method for managing employees

A group communication method performed in a group communication system comprising a first two-way radio configured to be carried by an employee who belongs to an nth (n=1, . . . , and N) group when the employees are grouped into first to Nth groups, a second two-way radio configured to be carried by an nth manager who manages employees who belong to the nth group, and a third two-way radio configured to be carried by a supervisor who supervises first to Nth managers,

• wherein an nth unique code is assigned to the nth group, and an (N+1)th unique code is assigned to an (N+1)th group which comprises the first to Nth managers and the supervisor, and
• wherein each of the first to third two-way radios comprises a first push-to-talk (PTT) button and a second PTT button,
• the method comprising:
• transmitting, by the first two-way radio, a voice packet comprising the nth unique code when the first PTT button or the second PTT button is pushed;
• processing and outputting, by the first two-way radio, a received voice packet when the received voice packet comprises the nth unique code;
• transmitting, by the second two-way radio, a voice packet comprising the nth unique code while the first PTT button is pushed;
• transmitting, by the second two-way radio, a voice packet comprising the (N+1)th unique code while the second PTT button is pushed;
• and
• processing and outputting, by the second two-way radio, a received voice packet when the received voice packet comprises the nth unique code or the (N+1)th unique code.