Limit entries with count in field

I used that build-in functionality to limit the number of entries allowed for my event and it works fine. Now I would like to add field "[ ] I have avec with me" -field the add two visitors to limit count at once. (I can also use select with counts if it's easier.)

Is there any easy way to do this kind of calculation to get right count?

Thanks. I made quick and dirty solution by combining couple of examples

function count_with_avecs($form){

  $count = 0;
  $leads = RGFormsModel::get_leads($form["id"]);

  foreach($leads as $id => $lead) {
	$count++;
	if( $lead['8.1'] == "KYLLÄ" ) $count++;
  }

  if( $count >= $form['limitEntriesCount'] ) {
	  $limit_message = $form['limitEntriesMessage'];
      add_filter('gform_get_form_filter', create_function('', "return '<p class=\"limitmessage\">$limit_message</p>';") );
  }

  return $form;
}

add_filter("gform_pre_render", "count_with_avecs");

TODO: fix if( $lead['8.1'] == "KYLLÄ" ) to search right field automaticly (This KYLLÄ means Yes and it's the value. It can be easily changed to field to have different count in it...)