Store and retrieve a variable in a Presenter course

Hi all, I'm sure this has been discussed to death somewhere along the line, but I need to present a choice to the participant in the form of a clickable button, store that selection in a variable, and then retrieve it later to determine which series of slides to display. I know it's not out-of-the-box functionality, but I'm sure one of you e-learning gurus has figured out a way to do it. What's the simplest way to accomplish that using Presenter '09? Thanks!