Number of groups N_group as a function of the projected linking length in units of the median projected intergalaxy separation (b_⊥) for a fixed α = 1.5 (Section 3.5). The number of groups for small b_⊥ values is low because only a small number of galaxies are too close to link together. On the other hand, for large values of b_⊥, N_group is also small because many galaxies link together to form percolated structures. By fixing α = 1.5, the number of selected groups maximizes at b_⊥ ∼ 1.3 and we use it as a suitable trade-off linking length for our group selection.