Creating a dialogue with Physics.OverlapSphere

I want to upgrade my dialogue system. right now I have a targeting system that ; if the target is selected it plays this line of code.

 selectedTarget.GetComponent<FirstNarratorComplete>().DisplayMenu = true;

Now how can I make a system were I can do that for Physics.OverlapSphere without creating a script for each of the characters?

Here is what I have so far:

using UnityEngine; using System.Collections;

public class inRangToTalk : MonoBehaviour {

 // Use this for initialization
 void Start () {
 
 }
 
 // Update is called once per frame
 void Update () {
     
     Collider[] cols = Physics.OverlapSphere(transform.position, radius);
     foreach (Collider col in cols){
         if (col && col.tag == "Player"){ 
             Quests script = col.GetComponent<Questst>();
             if (script.QuestOne ==true){
                         
             }
             if(Quests.QuestOne ==true) {
                 selectedTarget.GetComponent<FirstNarratorComplete>().DisplayMenu = true;
             }
         }
     }