What you most likely need to do is something like:
if (Input.touchCount > 0 && Input.touchCount < 2)
{
Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
RaycastHit hit;
if (Physics.Raycast(ray, out hit)) {
//more conditions here based on hit.collider.gameObject.name for example
}
}