Is it possible to skip data points in a 3D mesh plot?

 [x,y] = ndgrid(-100:100,-100:100);
 z = y.*x;
 mesh(x,y,z);

 z(find(z)>=6e3) = 0;

I want the mesh plot to skip all values above 6e3. Because on the xy plane points I plan to skip represent curves. I am not able to use 2D plot method to index x or y.

http://www.tiikoni.com/tis/view/?id=652cd3b to http://www.tiikoni.com/tis/view/?id=d917d02

Is it possible?

Thanks,