Preview multiple Visitor Groups directly while browsing your Optimizely site

Visitor groups are great - it's an easy way to add personalization towards market segments to your site. But it does come with it's own set of challenges if used intensively. For example it can be hard to predict how any given page will look for visitors with a specific combination of visitor groups - and viewing it in a proper way often requires more than what you see in the quick preview mode. Here's a bit of code that will help you out.