function plt_hide_rentsyst_menus() {
//Hide "Rentsyst".
remove_menu_page('rentsyst');
//Hide "Rentsyst → Rentsyst".
remove_submenu_page('rentsyst', 'rentsyst');
//Hide "Rentsyst → Design (new)".
remove_submenu_page('rentsyst', 'rentsyst-design-v2');
//Hide "Rentsyst → Catalog Options".
remove_submenu_page('rentsyst', 'catalog-options');
}
add_action('admin_menu', 'plt_hide_rentsyst_menus', 11);