UIMenuController submenu

Question

I'm trying to implement an UIMenuController with some UIMenuItems in a Mac Catalyst app with the following:

let menu = UIMenuController.shared
menu.menuItems = [itemA(), itemB(), itemC()]
menu.showMenu(from: someView, rect: someView.bounds)

// itemB and itemC are just as the following
private func itemA() -> UIMenuItem {
    let item = UIMenuItem(title: "Some item", action: #selector(test))
    return item
}

The menu is shown but I cannot find a way to create submenus, for example:

itemA() expands for itemB() and itemC()

How can I achieve this?

Example image