Wireless communication in a wireless system using a multiple user transmission opportunity is provided. The data blocks are organized in order of transmission priority based on access categories. Contention for access to the communication medium during a transmission opportunity period is based on a backoff timer of each access category and the transmission priority. Upon successful contention for a transmission opportunity period, during the transmission opportunity period, a data block of a primary access category is wirelessly transmitted from the wireless station to one or more primary destination wireless receivers. Simultaneously, a data block of a secondary access category is wirelessly transmitted from the wireless station to one or more secondary destination wireless receivers. Contending for the transmission opportunity period includes each access category contending for access to the wireless communication medium and a secondary access category selectively invoking communication medium access backoff based on one or more backoff events.