Hide sketch lines behind model geometry

Hi all...thank you in advance for your time.

 

I have a system model view on a drawing and a 2d sketch on the floor plane depicting the building walls.  I'd like to hide the parts of the floorplan sketch that fall behind the system model geometry....any ideas?  ,

 

I could extrude the floorplan by a thou, of course....but thought i'd ask...

Thanks again.

Kurt