I am running to this problem again and again... of confusing the unique and non unique ways for finding gameObjects.

If i have a child (let's say) trigger, i can access its parent by doing

yourgameObject.transform.parent.gameObject

This parent is a unique game object and if I clone twenty of those prefabs whenever I hit them I will get the right parent from the right corresponding hierarchy.

With

gameObject.FindWithTag "xxx"

I get a random first object that matches the criteria of my search. But If you duplicate ten prefabs with this code they won't work because it finds a random one (or the first one??). It is good for unique tags like "player" in a singleplayer game.

gameObject.Find "xxx/xxx/xxx"

you find the unique children.

Please let me know if I am right until here.

Is there any way to find a unique sibling(grandcousin!)? do I have to use root and then find ?

///////////////////// Edit after answer

after Ducks suggestion I did a code that looks like that to point to children gameObjects by name. I am still missing something I think but I works.

var allChildren = currentRoot.GetComponentsInChildren(Transform);
        for (var child : Transform in allChildren) 
        {
                    if(child.gameObject.name == "MyObject")
                    {
                    currentRemoteChild = child.gameObject ;

                    }

        }