private GameObject[] objects = GameObject.FindGameObjectsWithTag("mytag");
//Change private to public if you want it to be acessible from the inspector and other scripts.
//Add [HideInInspector] in front of public if you don't want it to be accessible in the inspector.
//Replace objects with the name of your array that is storing the GameObjects.
//Replace mytag with the tag you are looking for in the array.