Wpf: Merge toolbars between Window and UserControl?

[Andy]

Hi,

In WinForms, you could have a MDI child merge it's menu / toolbar
items automatically with the MDI parent's. I'd like to know if
there's a way to do something similar for Wpf, but with a UserControl
and host Window. Ideally, the solution would be a pure Xaml one.

Thanks!
Andy