Abstract: With the advent of e-commerce, web shops are becoming commonplace. The problem of shopping for complementary articles like furniture, upholstery, carpets, which are sold by independent web shops necessitates a functional integration mechanism for integrating the Web Shops of interest. To facilitate the shopper need for mixing and matching articles before taking the purchase decision, a specialized query mechanism is required. To address this need, we propose here an architecture for mediating complementary e-commerce sites, which is equipped with a special query mechanism providing prioritized querying and summary querying. Prioritized querying aids the shopper in specifying a series of prioritized alternative combinations of items desired. Summary querying aids the shopper in isolating the most suitable combination from among the retrieved matches.