How make some kind of shooting through glass?

Hello. So what i want is Instantiate texture on glass object and kill bot behind that glass. For instantiating holes i use this:

var bulletHole : GameObject;

function OnMouseOver(){
if (Input.GetMouseButtonDown(0)){
        var hit : RaycastHit;
        var hitRotation = Quaternion.FromToRotation(Vector3.back , Vector3.left);
        if(Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), hit))
         	   	 Instantiate(bulletHole, hit.point, hitRotation);	 

But objects behind glass are not receive raycast. How deal with this? How can two or more objects receive raycast if they placed behind each other?

Put the glass in a different layer and have raycasting ignore that layer using LayerMask. Although, if you want to glass to shatter at the same time, you may have to either do two raycasts (one with glass, the other without), or RaycastAll and see if the glass and the player are hit.