How can I create an ossia staff for a single bar or selection of bars in a piano score?

The question's in the title. I'm looking for a simple* way to create an ossia staff on a single bar, or selection of bars.

*By "simple", I mean something like "Add > Staff > Ossia Staff" whilst a bar is selected. If there isn't this simple a way of doing it, then I'll go ahead and post a feature request.