When I need to do this, I make the other values data-values and then use js to assign them to a hidden input
<select id=select>
<option value=1 data-othervalue=2 data-someothervalue=3>
//...
</select>
<input type=hidden name=otherValue id=otherValue />
<input type=hidden name=someOtherValue id=someOtherValue />
<script>
$('#select').change(function () {
var otherValue=$(this).find('option:selected').attr('data-othervalue');
var someOtherValue=$(this).find('option:selected').attr('data-someothervalue');
$('#otherValue').val(otherValue);
$('#someOtherValue').val(someOtherValue);
});
</script>