Magento: Enable default + 3rd party shopping cart simultaneously

I want to split test the default Magento shopping cart vs GoMage Lightcheckout shopping cart. While enabling the GoMage shopping cart, it overrides and disables the default cart. What I need is for you to enable the default shopping cart at URL 1, and enable the GoMage shopping cart at URL 2 so they are both active simultaneously. For example, the default cart would appear at: /store/checkout/6step/ While the GoMage would appear at: /store/checkout/onepage/ The URL can be anything, but they must both be active at the SAME time. Meaning they have to be always on. That way, I can redirect 50% of the traffic to url 1, and 50% to url 2, and track the conversion rates of each. GoMage lightcheckout documentation is located at: [login to view URL] You must understand requirements fully to be awarded the job.