Selecting multiple shapes only on the Top (Stacking Order)

[amstercannon]

I'm trying to figure out how to area select or custom select multiple shapes, but I only want the shapes on the Top of the Stacking order Selected, or a way to unselect shapes that are not on the top.

A little Background.
I'm running 2010 on Win7.
I'm working with a PDF file converted to a WMF (I also have a EMF version), brought into Visio, Ungrouped and saved as a VSD file.