Can admin menus have submenus?

Hello Grav Community,

My plugin uses the following code to create a menu at the admin plugin:
$this->grav['twig']->plugins_hooked_nav['MyMenu'] = ['route' => 'myroute', 'icon' => 'fa-quote-left'];
Is there a way to add a submenu to "MyMenu"?
What I'd like to accomplish is to have the submenu only visible after the user clicked on "MyMenu" and hide it again if the user navigates outside the plugin. Can this be done?

There's no logic in the Admin Plugin to handle submenus now, so the answer is no.

Thank you for the clarification.