Make a prefab gameobject trigger on dropping gameobject upon it

Hi!

I wonder if it's possible to have a prefab/gameobject to trigger when another object is dropped on it. Like in this image:

http://i.imgur.com/8T5mKfN.png

I have all these placeholder where to drop other objects. I need to be able to receive the dropped object and put it in a local property (lifeLine). Would that be possible?

This is just my test code so far:

 using UnityEngine;
 using System.Collections;
 
 public class LifelinePlaceholder : MonoBehaviour {
 
     public GameObject lifeLine;
     public string Name;
     // Use this for initialization
     void Start () {
         Debug.Log ("Yeah!");
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 
     void OnMouseUp()
     {
         Debug.Log (Name);
         //Debug.Log ("foobar");
     }
 
     void OnTriggerEnter2D(Collider2D other) {
         Debug.Log(other.gameObject);
     }
     
     void OnCollisionEnter2D(Collision2D other){
         Debug.Log(other.gameObject);
     }  
 }

Thanks in advance!