ok, I guess I had misunderstood your problem.
But the fact is that you actually can input multiple points to a GDL object with GH connection, independently of the object insertion point. You should use as parameter the coordinates of your sweeping path, in your case two points (x0,y0,z0 and x1,y1,z0)
then, use this object in GH, expose those coordinates parameters and feed them via your GH definition.
Let’s see if I take some time this weekend to demonstrate this graphically.