Hi Henry,
I'm glad that made sense!
In regards to your follow-up question regarding a custom Catalog Type, you can add certain door properties to a custom type, but obviously that type cannot actually be a door... if that makes sense. In the image below I've created a new Catalog Type and add a few property groups, added a Catalog Instance, then opened the Place User Defined tool to place one of these objects. Is this more or less what you intended?
