is there a way to clamp the Z information in unity with zigfu or ETC, so people don't get caught until a distance ?

i'm using Unity and Kinect together and everything's going pretty well, expect than my employer wants to limit the zdepth information, so people further than 2.5meter from the sensor don't get caught by it ( by default the sensor can detect people until 4meters far ).

my pipeline production can works with 2 unity wrappers 1/ the lastest kinect driver (1.6) with zigfu, and 2/ the beta kinectSDK64 with ETC wrappers .

So, does one of u know if there's a way to clamp the Z information in unity with zigfu or ETC, so people don't get caught until a distance ?