The possibility of tailoring by ion irradiation size, composition and topology of nanoclusters embedded in silica is systematically investigated in terms of irradiation parameters like ion mass, fluence, current density. By properly tuning the nuclear component of the energy released to the nanocomposite it is possible to create a halo of satellite clusters around the original ones. A direct correlation between the nuclear component of the energy released by the irradiating ions and the size and density of the satellite clusters is found. A second feature of this process is an elementally selective extraction of the Au-Ag alloy elements from the alloy with a prevalence of Au with respect to Ag.