Global Mapper v25.0

Spatially Thin LIDAR Points by Classification

The LIDAR thinning dialogue box is great, but let's say I want to thin only the ground points, but not other classificatins (such as transmission line points).. there seems ti be no easy way to do this. It would be great if I could specify a classification of points which will be spatially thinned. Is this already possible, am I missing it?
Thanks!