Methods and apparatus for transmission of data streams using a multicast packet format based on group identifiers (Group IDs) to deliver data to multiple recipient stations (STAs). Using Group IDs, an access point (AP) assigns multiple STAs to one or more groups, and uniquely assigns each STA to a particular position within the group, such that it can receive a requested data stream. A Group ID management action frame provided by the AP to an individual STA indicates to which group (or groups) the STA is assigned and the STA's position within the group, with which information the STA can determine whether a packet is intended for the STA and which portion of the packet to decode in order to receive requested data streams.