Abstract: A system for creating, displaying, and editing an intermediate data structure (IDS) that maintains a portion of a categorized data set (CDS) based upon an original set of hierarchically-related objects. A property of the objects is selected. The lowest-level objects matching the selected property are incrementally added to the IDS along with objects in a parent/child relationship with each added lowest-level object so long as those objects are not already within the category of the added lowest-level object. Special category objects are added to the IDS representing an object group with one value of the selected property. Objects stored within the IDS with this value are in a parent relationship with the category object. The objects stored within the IDS are displayed in an outline structure to show the functional relationships between the objects in each category.