A member device of a stacked switches system sends a first received unicast packet via an inter-group stack port which belongs to an aggregated stack link group on a forwarding path towards a different stack group when the first received unicast packet is to be egressed by another member device in the different stack group. The member device is further to send a second received unicast packet via an intra-group stack port on a forwarding path towards another member device in a same stack group when the second received unicast packet which is to be egressed by the another member device in the same stack group. The member device is further to send a third received unicast packet via a data port on the member device which associates with a egress port identification of the third received unicast packet when the third received unicast packet is to be egressed by the member device.