This read-write setting, meaningful only when activation type is switched, lets this port participate in a hunt group labeled A or B so incoming calls can roll over to another available port. It provides call overflow: if the first port in the hunt group is busy, the switch hunts to the next port sharing the same group designation. For example, assigning ports 1 through 4 all to hunt group a(2) lets an incoming call automatically ring the next free port in that group if the first one is already in use.