iPad SplitWindow layers - how to?

I have a SplitWindow in my iPad app with a MasterView and a DetailView. This all works fine. But I need to add "layers" in the sense that I need to stack 3 master views and 3 detail views, one on top of another. I need to be able to show/hide each master and detail depending on tab-style buttons being clicked. Each will be clones in terms of UI, but they all need to maintain their own unique data. I'm trying to achieve this by doing the following, depending on which tab/button was clicked:

splitwin.masterView = masterWin1; splitwin.detailView = detailWin1;

or

splitwin.masterView = masterWin2; splitwin.detailView = detailWin2;

But doing this seems to have no effect. For example, my masterWin1 and detailWin1 both have tables on them, rows, lots of content, etc. But my masterWin2 and detailWin2 are both empty windows. So when I click Button 2, I would expect to see the empty windows. And when I click Button 1, I'd expect to see all my content again.

So obviously I'm misunderstanding how this works. What am I doing wrong, and is there a cleaner way to achieve what I'm going for? Thanks!