Collecting linked elements in view without knowing linked file instance?

I just posted a link that might be helpful for someone who might have been visited this topic to figure out with same or similar reason. The guy in the link above provided a solution by geometry intersection between linked elements and a volume made based on section or scope boundary. I kind of understand Chris wanted to approach by using Revit API and so did I, but for now this could be a trick to get through our obstacle we had faced.