Top panels: group-galaxy cross-correlation functions of the mass-matched samples (ξ_G − gal). Upper panels: ξ_G − gal in the MS as a function of the normalised group-centric distance. Filled triangles (dotted lines) correspond to fossil groups, while open circles (dashed lines) correspond to normal groups with a magnitude gap ΔM₁₂ smaller than 0.5 mag. Error bars are computed using an analytic formula for the Poisson error in the clustering signal (Peacock 1999). Lower panels: ratios of cross-correlation functions (R_ξ) for fossils and groups with ΔM₁₂ < 0.5 mag. Error bars are computed using the usual formula of error propagation. Panels from left to right: different stages of the group evolution (see upper labels). Bottom panels: local over-density profile of galaxies around groups (Δ₅). Upper panels: Δ₅ in the MS as a function of the normalised group-centric distance. Filled triangles (dotted lines) correspond to galaxies around fossils groups, while open circles (dashed lines) correspond to galaxies around normal groups with ΔM₁₂ < 0.5 mag. Error bars represent the 35th and the 65th percentiles in the local density distribution at each distance bin. Lower panels: Ratios of local density profiles (R_Δ5) of fossils and groups with ΔM₁₂ < 0.5 mag. Error bars are computed using the usual formula of error propagation. Panels from left to right correspond to the stages of the group evolution (see upper labels).