function cpt_init() {

  $labels = array(
    'name' => 'Landen'
   );

  $args = array(
    'labels' => $labels,
    'public' => true,
    'publicly_queryable' => true,
    'show_ui' => true,
    'show_in_menu' => true,
    'query_var' => true,
    'rewrite' => array(
        'slug' => 'landen',
        'with_front' => FALSE,
    ),
    'with_front' => false,
    'capability_type' => 'post',
    'has_archive' => true,
    'hierarchical' => true,
    'menu_position' => null,
    'supports' => array( 'title', 'editor' )
  );

  register_post_type('landen',$args);

  $labels = array(
    'name' => 'Rondreizen'
  );

  $args = array(
    'labels' => $labels,
    'public' => true,
    'publicly_queryable' => true,
    'show_ui' => true,
    'show_in_menu' => true,
    'query_var' => true,
    'rewrite' => array(
        'slug' => 'landen/%landen%',
        'with_front' => FALSE,
    ),
    'with_front' => false,
    'capability_type' => 'post',
    'has_archive' => true,
    'hierarchical' => true,
    'menu_position' => null,
    'supports' => array( 'title', 'editor', 'page-attributes')
  );

  register_post_type('rondreizen',$args);


}

add_action( 'init', 'cpt_init' );

add_action( 'init', 'my_website_add_rewrite_tag' );
function my_website_add_rewrite_tag() {

    add_rewrite_rule( '^landen/([^/]*)/([^/]*)/?','index.php?rondreizen=$matches[2]','top' );
}


add_filter( 'post_type_link', 'my_website_filter_post_type_link', 1, 4 );
function my_website_filter_post_type_link( $post_link, $post, $leavename, $sample ) {
    switch( $post->post_type ) {

        case 'rondreizen':


            if ( $landen = array_shift( wp_get_object_terms( $post->ID, 'landen' ) ) ) {
                if ( isset( $landen->slug ) ) {
                    // create the new permalink
                    $post_link = home_url( user_trailingslashit( 'landen/' . $landen->slug . '/rondreizen/' . $post->post_name ) );
                }
                var_dump($landen);

            }

            break;

       break;

    }
    return $post_link;
}