A request for determining a unique object identifier for an object located somewhere within a plurality of data processing systems in a network may be received from an application by a single data processing in the network. A local object index containing object attribute records is searched for matches with specified input criteria and any matches are identified. A local search list is then consulted and, if other object indexes require searching, the request is forwarded to the next object index on the list together with an indication of the object index or indexes already searched. The inclusion of an indication of indexes already searched prevents a loop-back condition from occurring. As each object index is searched, the search list is consulted and, if additional object indexes remain to be searched, the request is propagated to the next object index and the results of searching a local object index are returned to an originating data processing system. Communication among data processing systems containing the respective object indexes is limited to requests and response, rather than entire object indexes, which facilitates operation over limited bandwidth communications links such as the Internet. The originating data processing system aggregates the search results for the network, which may be no matches, one match, or multiple distinct matches. Where a single match is determined, the corresponding object identifier is returned to the requesting application. Where multiple distinct matches are determined, an error condition is returned to the requesting application.