Wordpress - Add an admin page, but don't show it on the admin menu

From the docs on add_submenu_page(), you see that you can hide your submenu link from a top level menu item to which it belongs be setting the slug (1st argument) to null:

add_action( 'admin_menu', 'register_my_custom_submenu_page' );

function register_my_custom_submenu_page() {
    add_submenu_page( 
        null,
        'My Custom Submenu Page',
        'My Custom Submenu Page',
        'manage_options',
        'my-custom-submenu-page',
        'my_custom_submenu_page_callback',
    );
}

To highlight the desired menu item (e.g. 'all charts' when accessing the hidden 'edit chart' page), you can do the following:

add_filter( 'submenu_file', function($submenu_file){
    $screen = get_current_screen();
    if($screen->id === 'id-of-page-to-hide'){
        $submenu_file = 'id-of-page-to-higlight';
    }
    return $submenu_file;
});

Use a submenu page as parent slug. The admin menu has just two levels, so the imaginary third level will be hidden.

Sample code, tested:

add_action( 'admin_menu', 'wpse_73622_register_hidden_page' );

function wpse_73622_register_hidden_page()
{
    add_submenu_page(
        'options-writing.php',
        'Hidden!',
        'Hidden!',
        'exists',
        'wpse_73622',
        'wpse_73622_render_hidden_page'
    );
    # /wp-admin/admin.php?page=wpse_73622
}

function wpse_73622_render_hidden_page()
{
    echo '<p>hello world</p>';
}