excluding shipping if there are two or more product in cart

Hey guys,
I am using the easysite Mercury theme for my upcoming site. I have a simple question (at least I hope it is a simple one). How can I exclude shipping from the second product (and subsequent products) in the cart. Meaning, I only want to charge the customer once for shipping even though they have multiple items in the cart.
I have left the theme active on my test site for you to see what I mean.
Here is the code from the shopping cart functions file that I believe governs that area.
If someone could point me in a direction, I would greatly appreciate it.