You may also try using model terrains instead of HMPs.
First, create them all with same size say 20000 x 20000 quants,
place them all in the centre origin (postion : 0,0,0) in WED,
then set their skill1 for x-axis and skill2 for y-axis like :

terrain 1 = skill 1 : 0, skill 2 : 20000
terrian 2 = skill 1 : -20000, skill 2 : -20000 etc...

Code:

---

// assign this action to all terrains
action positionTerrain
{
  my.x = my.skill1;
  my.y = my.skill2;
  my.polygon = on;  // sensitive of collision

  // option : make them visible or invisble within
  // the camera view distance to increase fps
  while(my!=NULL)
  {
	if (vec_dist(my.x,camera.x) < camera.clip_far)  // play with camera.clip_far
	{
	   my.invisible = Off;
	} else {
	   my.invisible = On;
	}
	wait(1);
   }
  
}

---

It is much better than drag and place each terrain in WED.