The growing interest in the study of natural or artificial nanoscale structures stabilized by a corrugated surface calls for specific models adapted to the awkward symmetry of such systems. In this work the field susceptibility of a system composed of a finite number of micro-systems interacting with a solid surface is derived from a Dyson's type equation. The many-body character of the interactions between each particle, including reflection with the solid surface, is taken into account by a self-consistent procedure. We show that the calculation of this susceptibility provides a good basis to obtain the van der Waals dispersion energy inside a finite line of physisorbed atoms. We also discuss the possibility of applying this method to study optical energy transfer in complex systems.