title: Using one stock for multiple items in Magento
body: <p>Ok so what I want is to have multiple simple products draw from the same stock.</p>
  
  <p><strong>Scenario</strong></p>
  
  <p>I have a sinle nail file (<em>Stock:500</em>)
  I have a box of nail files (<em>50/box</em>)</p>
  
  <p>I want it so that if someone buys a box then it deducts from the 500 stock of the singles.  Essentially what we do is if someone buys a box, then we ship them 50 of the single files in a box.</p>
  
  <p>Any easy way to do this?</p>