Do not show tesselation edges

I have a mesh from a buffer geometry. To show the edges i use the edgesGeometry. This works but shows the edges which come out of the tessellation as well.

How can I make an edgesGeometry without them?

EdgesGeometry has the second parameter in its constructor:
thresholdAngle — An edge is only rendered if the angle (in degrees) between the face normals of the adjoining faces exceeds this value. default = 1 degree.
Try to play with this parameter, setting its value to something greater than 1. For example, 10 or 20.