Importing Surface as landXML issue

Hi,

When I import a surface triangulation from Autocad as a landXML file, the triangulation in Kubla seems to ignore the boundaries I set in Autocad. 

For example an "S" shaped driveway would join the extents so it would look like a rectangle. 

Is their a way I can import with the boundaries set so I just have the driveway shape?

Screenshot link 
https://drive.google.com/drive/folders/1...drive_link