Access manually instantiated object

This is pretty weird. I will try to explain it as good as i can...

I have a prefab of an object called myPrefabObj, that have attached script named (prefabObj_JS). Let's say that in the script i have this

 static var isEnabled

  function Start()
      {
         isEnabled = false;
      }

Then i instantiate that prefab 2 times in the scene (By hand NOT by script), so i have 2 objects in the scene, which are instances of the prefab and they both are called "myPrefabObj".

I have another object called "prefObjController", which have script. In the scipt i write this:

 public var myPrefabTrans : Transform;

 function OnTriggerEnter(col : Collider)
 {
     if (col.gameObject.tag == "Player")
         {
          myPrefabTrans.GetComponent(prefabObj_JS).isEnabled = true;
         }

after that i just insert one of the instantiated "myPrefabObj" objects in the prefObjController's custom created variable.

The problem is that when i trigger the "prefObjController", both instances of the "myPrefabObj" are getting changed their static variable "isEnabled" to true.

I got confused.. I was thinking that if i make custom variable and insert one of the myPrefabObj's into it, i will get controll only on that instance, not on all of them :\

How can i make it, so only the inserted instance of the prefab is getting controlled and NOT all of them in the scene...

Thank you... Thank you...