title: Validate a group of fields as required when at least one of them is filled
body: <p>In a basic registration screen (with button register records the screen) there are two panels:</p>
  
  <p>Data panel:</p>
  
  <p><img src="https://i.stack.imgur.com/6WIec.png" alt="enter image description here"></p>
  
  <p>Address panel:</p>
  
  <p><img src="https://i.stack.imgur.com/oxq8S.png" alt="enter image description here"></p>
  
  <p>I can register by completing only the Data panel. It is not necessary to fill the Address panel. However, if at least one field of the Address panel is filled, then all other fields in the same panel should be required.</p>
  
  <p><img src="https://i.stack.imgur.com/wRZG8.png" alt="enter image description here"></p>
  
  <p>How can I achieve this?</p>