While this isn't supported right now, we can fudge just a little bit and use one of the existing elements now. What others have done in the past is add a series of requirements of type “story” and reference them from use cases, other requirements, etc. as necessary.
Then using the filtering feature in CC2013, you can create and save a filter tab (on requirements, type "story"), so you can view them all together as you would for any other element's tabbed view.