how to target/tag multiple objects?

My problem is that I dont know how to shoot my homing missile and target multiple objects instead of one. May someone help me please?

var Speed : float;

var Turn : float;

private var rotationSpeed : float = -100.0;


function Start(){
}

function Update (){



transform.Rotate(Vector3(0, rotationSpeed * Time.deltaTime, 0));


	var targets: GameObject[] = GameObject.FindGameObjectsWithTag("Large"),("Medium"),
("Small"),("AlienShip");

	var closest: GameObject;
	var closestDist = Mathf.Infinity;
	
	for (Target in targets){
		var dist = (transform.position - Target.transform.position).sqrMagnitude;
		
		if (dist < closestDist){
			closestDist = dist;
			closest = Target;
			}
			
			
		}
		
		transform.rotation=Quaternion .Slerp(transform.rotation, Quaternion.
LookRotation(closest.transform.position-transform.position), Turn* Time.deltaTime);
		transform.position +=transform.forward*Speed*Time.deltaTime;
		
	}
	
	function OnCollisionEnter(Collision : Collision){
		Destroy(gameObject);
		
		}

If the question is how to scan though multiple tags please look at this example:

    var closest: GameObject;
    var closestDist = Mathf.Infinity;
 
 	var enemyTags: String[] = ["Large","Medium","Small","AlienShip"];
 	for (tag in enemyTags) {
    	var targets: GameObject[] = GameObject.FindGameObjectsWithTag(tag);
    	for (target in targets)	{
       		var dist: float = (transform.position - target.transform.position).sqrMagnitude;
 	        if (dist < closestDist) {
         		closestDist = dist;
         		closest = target;
         	}
        }
	}

However if the question is how to identify and target “clusters” of enemies to optimise splash damage, then please explain what is happening in you game in more detail.