Scatter plots of M_IGL against the four group properties with which this parameter is more strongly correlated, all measured at z = 0 (see Table 3). These properties are: (a) total system mass (M_grp), (b) total stellar mass (M_⋆), (c) total mass-to-stellar mass ratio (M_grp/M_⋆), and (d) mass of the first-ranked galaxy (m₁). Symbols for data points correspond to those used in Fig. 6. Since the values of all four properties are unaffected by the viewing direction, we only include, for the sake of clarity, the data points corresponding to the projections onto the XY plane. The solid grey lines and shaded bands represent the linear relationships and the associated 1σ uncertainties for each pair of parameters. The corresponding values of the Pearson correlation coefficients, r, are provided in each panel.