Handling Multiple HomePwner Archives?


I am working on tweaking my Homepwner for an app that I would like to create.
I am wondering how easy it is convert from just saving the one items.archive to allowing the user to have multiple archives. Basically making one additional step in the navController and letting the user pick from a list of files in his documents directory and whatever is selected feeds into the _allItems.

Any pointers on where to start?