making turret to kill each other but with same tag

when i add tag to parent game object the turret takes target parent game object, i want turret to take target all except the parent on which the child script is atached code is

 public Transform partToRotate;

 // Use this for initialization
 void Start () {
     InvokeRepeating("UpdateTarget", 0f, 0.5f);
 
 
 }
 void UpdateTarget ()
 {
     GameObject[] enemies = GameObject.FindGameObjectsWithTag (enemyTag);
     float shortestDistance = Mathf.Infinity;
     GameObject nearestEnemy = null;


     foreach (GameObject enemy in enemies)
     {
         float distanceToEnemy = Vector3.Distance(transform.position, enemy.transform.position);
         if (distanceToEnemy < shortestDistance)
         {
             shortestDistance = distanceToEnemy;
             nearestEnemy = enemy;
         }
     }
     
     if (nearestEnemy != null && shortestDistance <= range) {
         target = nearestEnemy.transform;
     }
     else
     {
         target = null;
     }



     }

 
 // Update is called once per frame
 void Update () {
     if (target == null)
         return;
 





     Vector3 dir = target.position - transform.position;
     Quaternion lookRotation = Quaternion.LookRotation(-dir);
     Vector3 rotation = lookRotation.eulerAngles;
     partToRotate.rotation = Quaternion.Euler(0f, rotation.y, 0f);

 }
 void OnDrawGizmosSelected ()
 {
     Gizmos.color = Color.red;
     Gizmos.DrawWireSphere(transform.position, range);
 }