Instantiating objects to create an infinite level.

I have a main object that has a North, West, South and East object as c$$anonymous$$ldren, ie the name of each object is N,W,S,E. I want the main object to be instantiated and put right in front of me starting with the respective end(when I am facing and going north and I reach the North-object, the main object should be instantiated so I enter South of the just instanced main object etc.). Also, it should remove all instantiated main objects being distant more than 4 instances of the main object of the player.

My code is t$$anonymous$$s and the problems are that rooms are copied randomly. Going back creates new instances in the same place or even different places, sometimes I get null exceptions for Destroy.

What to change:

 void OnTriggerEnter(Collider other)
     {
         //N:Z=1
         //O:X=1
         //W:X=-1
         //S:Z=-1
         if (other.gameObject.name == "N" && transform.forward.z > 0.8f)
         {
             Instantiate(Raum.gameObject, new Vector3(other.gameObject.transform.position.x, other.gameObject.transform.position.y, other.gameObject.transform.position.z + 8), Quaternion.identity);
         }
         if (other.gameObject.name == "S" && transform.forward.z < -0.8f)
         {
              Instantiate(Raum.gameObject, new Vector3(other.gameObject.transform.position.x, other.gameObject.transform.position.y, other.gameObject.transform.position.z - 6), Quaternion.identity);
         }
         if (other.gameObject.name == "W" && transform.forward.x < -0.8f)
         {
              Instantiate(Raum.gameObject, new Vector3(other.gameObject.transform.position.x - 6, other.gameObject.transform.position.y, other.gameObject.transform.position.z), Quaternion.identity);
         }
         if (other.gameObject.name == "E" && transform.forward.x > 0.8f)
         {
              Instantiate(Raum.gameObject, new Vector3(other.gameObject.transform.position.x + 6, other.gameObject.transform.position.y, other.gameObject.transform.position.z), Quaternion.identity);
         }
         Raeume = GameObject.FindGameObjectsWithTag("Raum").ToList();
         if (Raeume.Count > 3 && Raeume.First() != null)
             Destroy(Raeume.First());
         //Debug.Log(other.gameObject.name);
     }