Similar to Fig. 8, showing the difference in the group scaled mass ratio (Group Mass/L_opt, top) and group axial ratio (B/A, bottom). In both plots there appears to be a difference between the over- and underluminous groups in high L_opt systems. This is explored further in Sect. 5.2. However, a comparison of the full distribution for either parameter does not show significant differences between the overluminous and underluminous sample.