Destroy this game object will destroy all clone

Issue in a Simple Exercise : a red cube wil spawn: white cube
the white cube will move to the bottom, and when the distance between him and the red cube will be enought, will set a variable in the red cube "spawn.js" script so that the red cube will spawn another one. Actually the project work very well! The problem is when i try to destroy a white cube.
when i use:
Destroy(this.gameObject);
All the white will be destroyed...
WHITE CUBE SCRIPT

 #pragma strict
 private var flag = 1;
 public var spawn_distance :float;
 //the targhet is my spawn point. my objective is to spawn another of this 
 //object only when this is far away from the spawn point
 public var distance_targhet : GameObject;
 function Start () {
 
 }
 
 function Update () {
 
 
     if (flag == 1 ) {
         //ill find the spawn.js actually in the "red" object that is my spawn point
         var script : spawn = FindObjectOfType(spawn);
         //this object is mooving away from the spawn so when distance is enought ill will make the spawn poit ready to spawn
         var distance = Vector3.Distance(gameObject.transform.position, distance_targhet.transform.position);
     
         if (distance > spawn_distance) {
         flag=2;
         //the dist is OK now "red" will spawn another white cube
         script.can_spawn=1;
         
         }
     }
     if (flag >= 2 ) {
        //just to try after a few update i will destroy this object.
         flag=flag+1;
         Debug.Log(flag);
         if (flag == 100 ) {
             //THERE ARE MORE THAN 10 CLONE OF THIS OBJECT SPAWNED BUT THIS DESTROY ALL OF THEM .. NOT ONLY THIS ONE ?
             Destroy(this.gameObject);
         }
     
     }    
 }

RED CUBE SCRIPT

 #pragma strict
 //im a red cube on top of the layout
 public var can_spawn = 0;
 public var continusly_spawn = 0;//if set to 1 i will spawn whithout autorization
 public var thing_to_spawn : GameObject;  //this thing to spawn is a white cube 
 //the white cube will move away from my position and will set my "can_spawn" varible when 
 //the distance between us is enought 
 
 function Start () {
 
 
 }
 
 function Update () {
 
     if( can_spawn == 1 ) { //normally is set to 0, this will be set to 1 by a white cube when distance is enought
         
     Debug.Log("OK READY TO SPAWN"); //i will spawn an object then reset 
      Instantiate(thing_to_spawn, transform.position, transform.rotation); 
     can_spawn =0+continusly_spawn;
         
         
     }
     else Debug.Log("NOT READY TO SPAWN"); 
 
 }