<script type="text/javascript">
$(document).ready(function () {
  var sel = $('#sidlevel');
  function sidlevelOnChange() {
    var x = (sel.get(0).options[sel.get(0).selectedIndex] || {value: ';'}).value.split(';');
    $('#sid').get(0).value   = x[0];
    $('#level').get(0).value = x[1] || '';
  }
  sel.change(sidlevelOnChange);
  sel.keyup(sidlevelOnChange);
  sidlevelOnChange();
});
</script>

это скрытые поля, порождающие sid=...&level=...  в запросе
<input type="hidden" name="sid" id="sid" value="" />
<input type="hidden" name="level" id="level" value="" />

<select id="sidlevel">
  <option value="$PointProperty[Id]$;$PointProperty[level]$">$PointProperty[Title]$</option>
  <option value="$PointProperty[Id]$;$PointProperty[level]$">$PointProperty[Title]$</option>
  <option value="$PointProperty[Id]$;$PointProperty[level]$">$PointProperty[Title]$</option>
</select>