An apparatus for selecting one of a plurality of transaction queues from which to transmit a transaction out of a port of a switch. The apparatus includes a group indicator, for each of the queues, for indicating which one of a plurality of groups of the queues the queue belongs to. The apparatus also includes a group priority indicator, for each group of the plurality of groups, for indicating a priority of the group, the priority indicating a priority for transmitting transactions of the queues of the group relative to other groups of the plurality of groups. The apparatus includes selection logic, coupled to the group indicators and the priority indicators, configured to select a queue of the queues, for transmitting out of the port a transaction thereof, based on the group indicators and the group priority indicators.