How can you show that some radio buttons should be grouped together in a form (for accessibility)?

Copy<form>
  <fieldset>
    <legend>Choose one of these three items:</legend>
    <input id="one" type="radio" name="items" value="one">
    <label for="one">Choice One</label><br>
    <input id="two" type="radio" name="items" value="two">
    <label for="two">Choice Two</label><br>
    <input id="three" type="radio" name="items" value="three">
    <label for="three">Choice Three</label>
  </fieldset>
</form>