The role played by composite vector supermultiplets is studied in detail in the context of general supersymmetric confining theories. The structure of the low-energy effective action involving these vector supermultiplets is determined by use of the chiral WT identities. One of the most interesting outcome is the universal appearance of an effective gauge symmetry structure. Another is the emergence of a generationlike structure among the composite « matter » multiplets under this effective gauge symmetry.