Time evolution of the physical separation between the center of mass of the central galaxy (left panel: LG1-4469; right panel: LG1-4337) and its surviving satellites (upper panel) and merged galaxies (lower panel). Each continuous line represents a different satellite or merged galaxy, with line thickness proportional to their stellar mass ratio. The line color indicates the gas fraction of the satellite/merged galaxy at different stages of the interaction. Key events are highlighted with green and blue shaded regions, consistent with those shown in Fig. 8.