how do i delete a gameObject if touches another of its kind?

how do i delete a gameObject if touches another of its kind? I only want to delete one of them when they touch with each other using collider/trigger deletes both,both of the objects have to have the same script attached.

You can check instance id and delete the one with lower or higher instance id, that way only one of the objects will get deleted.

Use oncollisionenter, and detect collision with the gameobject you need. Then, delete it using destroy. See this:
http://unity3d.com/learn/tutorials/modules/beginner/physics/on-collision-enter