As someone writing scenarios, I want to be able to use another scenario as a Given, so that I don't have to write big long scenarios.

Not sure how this would work - at the moment we can get around it on the code side. I'm guessing we're looking for something like

Given the glider

where the_glider is a scenario file.

(What would we do if the_glider had two scenarios in it? Throw an exception, maybe?)