Situations involving structure-soil-structure interaction using SASSI 2000 and ACS SASSI protocols are concerned. Initially, techniques of elastic plane waves propagation in solids are used to understand SASSI free-field solution algorithm. Then, in SASSI scenery, some relevant properties of the model are varied and their influence on the interaction is analyzed. These parameters include: soil-main structure fundamental frequency ratio and between adjacent structures, structures mass relation and relative distance and embedment, between the main and the satellite structure. The responses are visualized trough SASSI 2000 acceleration transfer functions obtained in the central node of the top of the main structure. It is also proposed a new way of response visualization: the structural mechanical viscoelastic compliance, defined as the system ability to catch mechanical energy form the ground excitation and to keep it under a viscoelastic deformation state. It is suggested as a preliminary analysis stage to evaluate the influence of the satellite system in the main system response. A preliminary study on ground motion spatial variation using the ACS SASSI, version 2.2, protocol is also presented. One compares the influence of this consideration in the free-field solution, when the incoherence models available in the protocol are used. A couple of guide learnings and suggestions are left to the reader.