Opening KML File in active ArcMap Window

Hi,

I'm writing a program which needs to interface with ArcMap, I need to import a KML file and typically I would run it just by calling
ArcMap.exe <path to KML file>

The problem is, this loads a new session of ArcMap. Is there a way I can have it open in a copy currently running? I couldn't find any pages with commandline switches for ArcMap.

Thanks