having a hard time with multiple colliders

Hi. I'm trying to create a multiplayer platformer and I'm trying to create a store. When the player is over the store, a text that saids "press A" appears. Once the player gets the item text will disappear even when the player is over the shop collider.

This is fine for 1 player but I'm having a really hard time doing this with multiple players. I want the text to show when theres 1 or more players colliding with the store and within those players if anyone doesn't have an item the text will be displayed.

Is there a way to find out exactly what objects are overlapped with the collider?

Heres my code but I feel like i'm over complicating things. And it only works when theres 1 player.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class InventoryShopList : MonoBehaviour
5. {
6.     public string crossbow,bomb;
7.     public enum InventoryItem { crossbow,bomb}
8.     public InventoryItem myInventoryItem;
9.     public string pickupID;
10.  
11.     private PlayerScript _playerscript;
12.     private SpriteRenderer _buttonDisplay;
13.     private bool _isTouching, _hasInventory;
14.     private PlayerScript _p1,_p2, _p3, _p4;
15.     private bool _bool1,_bool2, _bool3, _bool4, _anyPlayerWithInventory;
16.  
17.  
18.     //sets up the inventory for the player
19.     public GameObject GetInventory (GameObject go)
20.     {
21.         switch (myInventoryItem)
22.         {
23.             case InventoryItem.crossbow:
24.                 go = Resources.Load<GameObject>("Prefabs/StartPointCrossbow");
25.                 pickupID = crossbow;
26.                 break;
27.  
28.             case InventoryItem.bomb:
29.                 go = Resources.Load<GameObject>("Prefabs/StartPointCrossbow");
30.                 pickupID = bomb;
31.                 break;
32.  
33.             default:
34.                  break;
35.         }
36.         return go;
37.     }
38.  
39.  
40.     void Start()
41.     {
42.         _buttonDisplay = transform.Find ("button_a").GetComponent<SpriteRenderer>();
43.     }
44.  
45.  
46.     void OnTriggerEnter2D (Collider2D col)
47.     {
48.         if (col.tag == "Player")
49.         {
50.             //_isTouching = true;
51.             _playerscript = col.GetComponent<PlayerScript>();
52.             if (_playerscript.playerID == PlayerScript.PlayerID.Player1)    _p1 = col.GetComponent<PlayerScript>();
53.             if (_playerscript.playerID == PlayerScript.PlayerID.Player2)    _p2 = col.GetComponent<PlayerScript>();
54.             if (_playerscript.playerID == PlayerScript.PlayerID.Player3)    _p3 = col.GetComponent<PlayerScript>();
55.             if (_playerscript.playerID == PlayerScript.PlayerID.Player4)    _p4 = col.GetComponent<PlayerScript>();
56.         }  
57.     }
58.  
59.     public bool IsTouching() //check if player/s is touching the collider
60.     {
61.         _isTouching = gameObject.GetComponent<BoxCollider2D>().IsTouchingLayers(LayerMask.GetMask("Player"));
62.         return _isTouching;
63.     }
64.      
65.     void Update()
66.     {
67.           IsTouching();
68.         if (_isTouching)
69.         {
70.             if (_p1 != null) _bool1 = _p1.hasInventory; else _bool1 = false;
71.             if (_p2 != null) _bool2 = _p2.hasInventory; else _bool2 = false;
72.             if (_p3 != null) _bool3 = _p3.hasInventory; else _bool3 = false;
73.             if (_p4 != null) _bool4 = _p4.hasInventory; else _bool4 = false;
74.         }
75.         if (!_isTouching)
76.         {
77.             if (_bool1 == true) _bool1 = false;
78.             if (_bool2 == true) _bool2 = false;
79.             if (_bool3 == true) _bool3 = false;
80.             if (_bool4 == true) _bool4 = false;
81.         }
82.            
83.         _anyPlayerWithInventory = _bool1 | _bool2 | _bool3 | _bool4;
84.  
85.         if(_playerscript != null)
86.         {
87.             if( _isTouching)
88.             {
89.                     _buttonDisplay.enabled = true;
90.             }
91.  
92.             if (!_isTouching || _anyPlayerWithInventory)
93.             {
94.                 _buttonDisplay.enabled = false;
95.  
96.             }
97.         }
98.     }
99. }
100.