In one of many possible implementations, an exemplary system includes a data integration subsystem configured to maintain a baseline data structure representing a base set of data relationships. The data integration subsystem in further configure to maintain a mapping of the baseline data structure to local data maintained by a plurality of local data subsystems. The system further includes a portal subsystem configured to provide a first customizable data structure associated with the baseline data structure for user access, create a copy of at least a subset of the baseline data structure, and provide a second customizable data structure associated with the copy of the baseline data structure for user access. The first and second customizable data structures are independently customizable to represent different custom sets of data relationships.