Galaxy r-band luminosity ranking for different pairs classified as M, T and N (solid, dotted and dot-dashed lines, respectively) in all groups, with a minimum number of 4 members (upper panel) and in groups with Lum_Group > 10^10.6   L_⊙ (lower panel). The dashed lines represent all the group galaxy members without near companions. The number 1 indicates the most luminous galaxy in the group, number 2 the second most luminous galaxy, and so on.