title: Always charge shipping for some items, even with rule "Free shipping for orders above $xx"
body: <p>I have an ecommerce and there's a little thing haunting me for the past few days.</p>
  
  <p>I would like to give my customers FREE SHIPPING on orders above $50 (or 100, 150. Doesn't really matter.)</p>
  
  <p>But <em>on some specific items</em> I will ALWAYS charge the shipping, so it should overwrite the Free Shipping rule.</p>
  
  <p>Example:</p>
  
  <ul>
  <li>Item A ($40) added to the cart => Cart Total = $40 => NO FREE SHIPPING</li>
  <li>Item B ($30) added to the cart => Cart Total = $70 => FREE SHIPPING</li>
  <li>Item C should always charge shipping. So if Item C ($5) is added to the cart, the new cart value should  be:
  $40 + $30 + $5 + SHIPPING for item C.</li>
  </ul>
  
  <p>How can I achieve this?</p>