title: Open Graph (beta) - using global actions and global objects together with custom ones
body: <p>My scenario is the following:</p>
  
  <p>I want to create a custom object called Music Video (because I don't see a global one) create a property for it of object type Song (I assume there's a global object Song, with artist, title, album, etc properties) and I also want to hook it up to the global action Watch.
  Is this possible? If not, what workaround do you suggest?</p>