Assign same value to multiple instances of the same prefab

I made a grid of gameobjects from the same prefab that when one of those GO is clicked, it is destroyed and another gameobject (Pipe) is instantieted on the same position is that "position holder" GO.

The problem is: to know what kind of pipe is to be set, I assign a value to it. The "holder" GO is supposed to read it and instantiate that pipe on it's same position. Only the first instance of these "holders" is changing it's value, all others remain unchanged.

Also, when I put a pipe on that very first "holder" GO, the next one to it now changes it's value and I can manage to change it also. So basically, the script is somehow allowing me to change it sequentially but not in any random order I want.

     void OnGUI()
     {
         //SetPipe setPipeScript = GetComponent<SetPipe>();
         SetPipe setPipeScript = GameObject.FindGameObjectWithTag("Holder").GetComponent<SetPipe>();
         selGridInt = GUI.SelectionGrid(new Rect(50, 70, 100, 500), selGridInt, pipeShape, 1);
         {
             switch (selGridInt)
             {
                 case 0:
                     setPipeScript.pipeSelect = 1;
                     break;
 
                 case 1:
                     setPipeScript.pipeSelect = 2;
                     break;
 
                 case 2:
                     setPipeScript.pipeSelect = 3;
                     break;
 
                 case 3:
                     setPipeScript.pipeSelect = 4;
                     break;
 
                 case 4:
                     setPipeScript.pipeSelect = 5;
                     break;
 
                 case 5:
                     setPipeScript.pipeSelect = 6;
                     break;
 
                 case 6:
                     setPipeScript.pipeSelect = 7;
                     break;
             }
 
         }
     }

This is the GUI code I put in another GO, a GameManager.

 public class SetPipe : MonoBehaviour {
 
     public Transform pipe1; //T
     public Transform pipe2; //L Superior
     public Transform pipe3; //L Superior Invertido
     public Transform pipe4; //L Inferior
     public Transform pipe5; //L Inferior Invertido
     public Transform pipe6; //Vertical
     public Transform pipe7; //Horizontal
 
     public int pipeSelect;
     void Start () 
     {
 
     }
     
     void Update () 
     {
          
     }
 
     void OnMouseOver()
     {
         if (Input.GetMouseButtonDown(0))
         {
             switch (pipeSelect) //Alterado por método OnGUI em GameManager
             {
                 case 1:
                     Debug.Log("Cano T");
                     Instantiate(pipe1, gameObject.transform.position, Quaternion.Euler(0, 0, -90));
                     Destroy(gameObject);
                     break;
 
                 case 2:
                     Debug.Log("Cano L Inferior");
                     Destroy (gameObject);
                     Instantiate (pipe2, gameObject.transform.position, Quaternion.identity);
                     break;
 
                 case 3:
                     Debug.Log("Cano L Inferior Invertido");
                     Destroy(gameObject);
                     Instantiate (pipe3, gameObject.transform.position, Quaternion.identity);
                     break;
 
                 case 4:
                     Debug.Log("Cano L Superior");
                     Destroy (gameObject);
                     Instantiate(pipe5, gameObject.transform.position, Quaternion.identity);
                     break;
 
                 case 5:
                     Debug.Log("Cano L Superior Invertido");
                     Destroy (gameObject);
                     Instantiate (pipe4, gameObject.transform.position, Quaternion.identity);
                     break;
 
                 case 6:
                     Debug.Log("Cano Vertical");
                     Destroy (gameObject);
                     Instantiate (pipe6, gameObject.transform.position, Quaternion.identity);
                     break;
 
                 case 7:
                     Debug.Log("Cano Horizontal");
                     Destroy (gameObject);
                     Instantiate (pipe7, gameObject.transform.position, Quaternion.Euler(0, 0, -90));
                     break;
             }
         }
     }
 }

This is the code that set up the pipes. I tested it without the condition inside the mouse method and it actually works that way, but doing so will only allow one of the pipes to be placed (but it allows it to be placed anywhere and non-sequencially).

Took a couple of PS to help show it.

These buttons on the side change the value of the Pipe Select.

Thanks for the help, guys. :D