title: jquery validate plugin combine field validation
body: <p>On one form I have City, State, ZIP code on one line in the form (inside one block element).</p>
  
  <p>My error div for the validate plugin slides nicely under the form div so that message is contextual.</p>
  
  <p>Is there a way to combine a rule so that it's not 3 separate validation rules?  In other words, if city is blank, or state is blank, or ZIP is blank, I want to trigger just one error message div "City, State and ZIP code are required".  Likewise if 2 of 3 or 3 of 3 are blank I still want to have just one error div returned by validate.</p>