<form>
<input type="radio" name="group1" value="somevalue" /> Some Value<br />
<input type="radio" name="group1" value="somevalue2" /> Some Value 2<br />
<input type="radio" name="group1" value="somevalue3" /> Some Value 3<br />
<input type="radio" name="group1" value="somevalue4" /> Some Value 4<br />
<input type="radio" name="group1" value="somevalue5" /> Some Value 5<br />
<input type="radio" name="group1" value="somevalue6" /> Some Value 6<br />
<br />
<input type="radio" name="group2" value="somevalue" /> Some Value<br />
<input type="radio" name="group2" value="somevalue2" /> Some Value 2<br />
<input type="radio" name="group2" value="somevalue3" /> Some Value 3<br />
<input type="radio" name="group2" value="somevalue4" /> Some Value 4<br />
<input type="radio" name="group2" value="somevalue5" /> Some Value 5<br />
<input type="radio" name="group2" value="somevalue6" /> Some Value 6<br />
</form>
As Dagon says radio is the way to go. Put this in an html page and see how it works.