Not out of the box, unfortunately... The initial purpose of simple-navigation was to render navigations. The ability to render breadcrumbs was only added through a custom renderer. So for a navigation, it never makes sense to render the navigation only if a level 2 navigation is active.
But on the other hand I think it would be pretty easy to create a custom renderer based on the current breadcrumbs renderer (SimpleNavigation::Renderer::Breadcrumbs) where you can implement this behaviour. If you need more help with this, let me know...
Andi