SIS model on the multi-modal SARCS candidates. The centre chosen for the shear profile is located either on the strong-lensing system (black open squares), at the middle of the 2 luminosity over-densities (red open circles) or on the luminosity peak not associated to the strong lensing features (green open triangles). The measured dispersion at the three different positionings can be used as an indicator of the dominance of the strong lens within its group.