Thanks as always ...
Referencing your only sample:
Is it possible to limit the creation of groups per (visual) parent group? For example, in the provided sample grouping occurs at the first ResourceType (Categories) and then subgroups are created for each Category.
Is it possible to supress this iteration for selected Categories of choice? So we'd have something like subcategories for "Business Layer" (200, 250, 300, 400) but have no subcategories for "Data layer".