Admin custom page filter

I have the following code which works perfectly to get me a filter of all the terms (from section) in the custom post type module.

/* Create filter-through Module's by Section
---------------------------------------------------*/
add_action('restrict_manage_posts', 'restrict_manage_posts_section');
function restrict_manage_posts_section()
{
    global $post_type;
    if ( is_object_in_taxonomy( $post_type, 'section' ) )
    {
        $dropdown_options = array(
            'show_option_all' => __( 'View all sections' ),
            'hide_empty' => 0,
            'hierarchical' => 1,
            'name' => 'section',
            'show_count' => 0,
            'taxonomy' => 'section',
            'orderby' => 'name',
            'selected' => $cat
        );

        add_filter('wp_dropdown_cats', 'wp_dropdown_section_filter', 10);
        wp_dropdown_categories( $dropdown_options );
        remove_filter('wp_dropdown_cats', 'wp_dropdown_section_filter', 10);
    }
}

function wp_dropdown_section_filter($select)
{
    $terms  = get_terms('section', array('hide_empty' => false));
    foreach( $terms as $term )
    {
        $select = str_replace('value="'.$term->term_id.'"', 'value="'.$term->slug.'"', $select);
        if (isset($_GET['section']) && $term->slug == $_GET['section']){
            $select = str_replace('value="'.$term->slug.'"', 'value="'.$term->slug.'" selected', $select);
        }
    }
    return $select;
}

Now what my problem is, is getting this to do the same as above, but to filter the parent pages of module. Heres the code i have so far, which gets me the list of all the parent pages in the post type module, the part i cant get is once you click the filter button, to have everything filter properly. I want the outcome to be the parent page and all its children will be shown.

/* Create filter-through Module's by Parent Module
---------------------------------------------------*/
add_action('restrict_manage_posts', 'restrict_manage_posts_module');
function restrict_manage_posts_module()
{
    global $post_type;
    if ( is_object_in_taxonomy( $post_type, 'section' ) )
    {
        $dropdown_options = array(
            'show_option_none' => __( 'View all modules' ),
            'depth' => 1,
            'hierarchical' => 1,
            'post_type' => 'module',
            'sort_column' => 'name',
            'selected' => $page
        );

        add_filter('wp_dropdown_pages', 'wp_dropdown_module_filter', 10);
        wp_dropdown_pages( $dropdown_options );
        remove_filter('wp_dropdown_pages', 'wp_dropdown_module_filter', 10);
    }
}

function wp_dropdown_module_filter($select)
{
    $pages  = get_pages(array());
    foreach( $pages as $page )
    {
        $select = str_replace('value="'.$page->ID.'"', 'value="'.$page->post_name.'"', $select);
        if (isset($_GET['module']) && $page->post_name == $_GET['module']){
            $select = str_replace('value="'.$page->post_name.'"', 'value="'.$page->post_name.'" selected', $select);
        }
    }
    return $select;
}