I don’t think its impossible. I moved my primary website into WordPress using the pinboard theme, when I was finish I updated the theme of my blog to pinboard so they look the same. Now I want to export my blog into my new wordpress website. But the blog has a different sidebar (widgets) displayed. So I need to be able to switch between two different sidebars. One when post are displayed and another when pages are displayed. Sounds like an if/than situation and some php code.