you can add HTML ... in * the template file at events-manager/templates/forms/event-editor.php */ add_filter('em_event_save','custom_event_save',1,2); function custom_event_save($result,$EM_Event){ if ( is_multisite() ){ $EM_Event->blog_id = ( !empty($_REQUEST['blog_id']) ) ? $_REQUEST['blog_id']:get_current_blog_id(); } return $result; }