如何对元素进行分组

I got this form:

我有这种形式:

<form method="post" action="" accept-charset="utf-8"> 
<p>
  <label>first_field</label><br />
  <input type="text" id="first_field" name="points[]" /><br />
  <input type="radio" value="inside" name="group_1" checked /><br />
  <input type="radio" value="outside" name="group_1"><br />
</p>
<p>
  <label>second_field</label><br />
  <input type="text" id="second_field" name="points[]" /><br />
  <input type="radio" value="inside" name="group_2" checked /><br />
  <input type="radio" value="outside" name="group_2"><br />
</p>
</form>
<form method="post