An apparatus for grouping a plurality of stations in a multi-transmission environment includes an SNR (Signal to Noise Ratio) measuring unit configured to measure SNR values of the stations existing in the multi-transmission environment. Further, the apparatus includes a grouping unit configured to group the stations into several subgroups depending on the SNR values, wherein a leader is defined in each subgroup. Furthermore, the apparatus includes a control unit configured to determine an MCS (Modulation and Coding Scheme) intended for each subgroup and form different A-MPDU (Aggregated MAC Protocol Data Unit) for each subgroup separately to send to each subgroup in a multicast transmission.