Multiple game objects same script

I have multiple platfforms with same script MovingPlatform.cs.

My problem is that when one platform (game object) is on scene everything is ok, but when I have more objects, script is setting player.transform.parent to null even if I raycast with one of the platforms.

     if (_controller.RayCasting())
     {
      player.transform.parent = transform;
     }
     else
     {
      player.transform.parent = null;
     }

How to stop this from happening and have same behavior as with only one platform on scene!?