title: jQuery Validate elegant conditional logic
body: <p>I am validating a form with the jQuery validation plugin (using the plugin is required, as I have other functionality that needs the plugin).  It has the following fields:</p>
  
  <p><code>phoneNumber</code>
  <code>firstName</code>
  <code>lastName</code>
  <code>city</code>
  <code>zip</code></p>
  
  <p>The form is considered valid when one of the following statements is true:</p>
  
  <ul>
  <li><code>phoneNumber</code> is valid</li>
  <li><code>firstName</code> <code>lastName</code> <code>city</code> are all valid</li>
  <li><code>firstName</code> <code>lastName</code> <code>zip</code> are all valid</li>
  </ul>
  
  <p>I know how to require each field and use the other validation methods (I even have my own for the zip), but I am trying to figure out an elegant solution to implement the logic I described above.  Is a custom method or validation groups the best way to handle this?</p>