The invention relates to a method and system for simultaneous transmission of data from two or more wireless communication device during a transmission opportunity otherwise reserved for a single communication device. The invention proposes collaboration among the group of communication devices to reserve a transmission opportunity on a composite channel comprising of a plurality of sub-channels for the entire group and to efficiently manage allocation of the sub-channels for simultaneous data transmission from two or more devices. In the main aspect of the invention, the collaboration takes the form of grouping the sub-channels in the reserved composite channel so as to allow two or more stations to transmit data simultaneously over a contiguous frequency band. The collaboration among the group of communication devices may be in a managed or an ad hoc mode. The invention is particularly relevant to the IEEE 802.11 ac communication standard.