Point cloud in ArchiCAD is converting into GDL script. It is possible to cut it using GDL commands cutpoly and cutplane. ArchiCAD already using cutplane on the floor plan - when it's possible to set horizontal limits.
Adding additional cutting planes in GDL script will result of disappearing part of point cloud.
It is not something straight forward like using SEO, but it is possible to create additional GDL object with cutting planes and editable hotspots (and comfortable interface), linking original file as a macro.
See attached below image, showing 3D script of point cloud object - it's not really complicated.