Custom Snap Points In Linked Objects

I'd like to request a feature for custom snappable points in linked objects from models stored in external files. Currently the 1 snappable center point makes it very challenging to position composited scenes accurately, whereas custom snap points designed around the linked model would make the task even simpler than it is currently with vertex based snapping in the same model/scene (i.e. you could have an unrenderable mesh which constitutes "snap points" with vertices in the center of a pipe.)