/about-us (used as a parent holder only)
/about-us/history (real page)
/about-us/team (real page)
/about-us/industry (real page)

<?php
/*
 * Template Name: Redirector
 * Description: Empty Holder (redirect page)
 */


    $rp = new WP_Query(array(
        'post_parent'   => get_the_id(),
        'post_type'     => 'page',
        'order'         => 'asc',
        'orderby'       => 'menu_order'
    ));

    if ($rp->have_posts())
        while ( $rp->have_posts() ) {
            $rp->the_post();
            wp_redirect(get_permalink(get_the_id()));
            exit;
        }
    wp_redirect(dirname(home_url($wp->request)));
    exit;

<?php
/*
 * Template Name: Parent Menu
 * Description: Redirects empty parent page to first child page
 */

# Parent menu goes to first child page
# askwpgirl.com/redirect-parent-page-first-child-page-wordpress
$child_page = get_pages( "child_of=" . $post->ID . "&sort_column=menu_order" );
if ( $child_page ) {
    $parent_page = $child_page[0];
    wp_redirect( get_permalink( $parent_page->ID ) );
}

/wp-content/themes/child-theme