Need method to subtract one object from another

I have a vector graphic in ai format.  There are three objects (people) with the left object in front, middle object behind the front and right object in the back.  I want the left object to cut the vectors behind it from the middle object and then  the middle object to cut the vectors behind it of the right object. I have tried pathfinder without the result I want.  The end use is with a laser or mill to follow the vectors.  Do I need to try paths?  

Steve.