Remove available options PHP

Thanks very much legolasbo for the hook. It works as expected. Here is some code which might help someone :-

/**
* Implements hook_select_or_other_available_options().
*
*/
function mymodulename_select_or_other_available_options($entity_type, $bundle, $field_name){

  $kv_options = array();
  // for course-deliverer->field_crs_id_or_email_address get key|value list of course deliverers for select_or_other
  if ($entity_type === 'node' && $bundle === 'course_deliverer' && $field_name === 'field_crs_id_or_email_address') {
    $result = db_query("SELECT node.nid AS nid, node.title AS title
      FROM {node} node
      WHERE (( (node.status = '1') AND (node.type IN  ('course_deliverer')) ))");

    // make sure some row/s has/have been found
    if ($result) {
      // add all found rows to the KV array
      foreach($result as $row) {
        // the nid with be the key and the node title will be the value
        $kv_options[] = $row->nid . '|' . $row->title;
      }
    }
  }
  return $kv_options;
}