Delete from a list duplicate points with the same x and y coordinates

Hello guys,
We want to generate a topo from floor surfaces points.
The problem that we are having is that we have points that have the same coordinates X and Y but different Z and this is an issue for the topo creation.
We would like to modify the list by deleting the duplicate with less Height.
I am sure this is an easy manage list problem but we are not sure how to start.
Any ideas???

Problem solved, we have used a node called spings.Points.PruneDuplicates+
Thank you very much!!!