AutoCAD Map 3D :: Polygon Data From Elevation Of Internal Points

I have thousands of polygons (and circles) which represent 2D foundation detail.

I have XY Location data (XLS, CSV etc) and Z's for the tops and bottoms of all these objects. (and hence, AutoCAD points)

I have used SHP data before (for the building footprints, and tops) whereby the top and base data is included in the data and I have use mapimport with change properties to thicken polylines and create quick 3D objects above ground.(This was created by others using a method similar to what I want, but in a competitors GIS...)

I need to do the same with the footings.

How can I create a "search" that says - for each polygon, look for a single point inside, and report its elevation and attached that to the polygon as data? Or, create a SHP of all these polygons with RL data queried of the internal point.

The points arent necessarily at centroid, which could be an issue. (Most are, however)

There is no keyID data between the polys and the points (so data joins wont work)

A friend did this very quickly for me in an ESRI Package, surely MAP can do the same!?

Map 3D 2012, and a monstrously powerful CAD workstation... just, er, not the knowledge to yet pull this off.