c# destroy Gameobject on 0 hp

i have three monsters there skeleton clones when the game starts up i only want 1 to die if the hp drops to zero not all of them die cause they have the same name i have my targeting script witch i can target the closest enemy in the game to the player and so on it has a

here's my targeting script

/// /// This script can be attached to any permanent gameobject, and is responsible for allowing the player to target different mobs that are with in range /// using UnityEngine; using System.Collections; using System.Collections.Generic;

public class Targetting : MonoBehaviour { public List targets; public Transform selectedTarget;

 private Transform myTransform;
     
 // Use this for initialization
 void Start () {
     targets = new List<Transform>();
     selectedTarget = null;
     myTransform = transform;
     
     AddAllEnemies();
     
 }
 
 public void AddAllEnemies() {
     GameObject[] go = GameObject.FindGameObjectsWithTag("Enemy");
     
     foreach(GameObject enemy in go)
         AddTarget(enemy.transform);
 }
 
 public void AddTarget(Transform enemy) {
     targets.Add(enemy);
 }
 
 
 private void SortTargetsByDistance() {
     targets.Sort(delegate(Transform t1, Transform t2) {
             return Vector3.Distance(t1.position, myTransform.position).CompareTo(Vector3.Distance(t2.position, myTransform.position));
             });
 }
 
 //if we do not have an enemy targeted ywt, then find the clostest one and target him
 //if we do have an enemy targeted, then get the next target
 //if we have the last target in the list, then get then first target in the list
 private void TargetEnemy() {
     if(selectedTarget == null) {
         SortTargetsByDistance();
         selectedTarget = targets[0];
         

     }
     else {
         int index = targets.IndexOf(selectedTarget);
         
         if(index < targets.Count - 1) {
             index++;
         }
         else {
             index = 0;
         }
         DeselectTarget();
         selectedTarget = targets[index];
     }
     SelectTarget();
 }
 
 private void SelectTarget() {
     selectedTarget.renderer.material.color = Color.red;
     
     PlayerAttack pa = (PlayerAttack)GetComponent("PlayerAttack");
     
     pa.target = selectedTarget.gameObject;
 }
 
 private void DeselectTarget() {
     selectedTarget.renderer.material.color = Color.white;
     selectedTarget = null;
 }
 
 // Update is called once per frame
 void Update () {
     if(Input.GetKeyDown(KeyCode.Tab))
         TargetEnemy();
 }
 
 

}