Reference is now made to FIG. 3, which is a simplified block diagram illustration of a combined system of the type shown in FIG. 1, which incorporates elements of at least one of the types shown in FIGS. 2A and 2B. As seen in FIG. 3, multiple groups of detector modules 106 (FIG. 1) may communicate via multiple computer networks, through management software described hereinbelow with reference to F