function plt_hide_yaymail_menus() {
//Hide the "YayCommerce" menu.
remove_menu_page('yaycommerce');
//Hide the "YayCommerce → Help" menu.
remove_submenu_page('yaycommerce', 'yaycommerce-help');
//Hide the "YayCommerce → Other plugins" menu.
remove_submenu_page('yaycommerce', 'yaycommerce-other-plugins');
}
add_action('admin_menu', 'plt_hide_yaymail_menus', 102);