Two single post templates (NOT category-based)

Hello, all. I’ve tried to brainstorm a solution to this problem without delving into advanced PHP, but am stuck. Perhaps someone is generous enough to provide a solution.

I’ve integrated Mal’s Ecommerce shopping cart into my site where user’s can buy a media file pertaining to the post I make. When clicking the Buy button, it will call the name of the post and add it into the shopping cart. However, I wish to now add “impulse” items to buy before they checkout where it will silently add the item into their cart and then display recommended items to buy.

My original idea was to have them redirected to the single post page, and then beneath the post, it asks would you like to add additional items to their shopping cart — the catch here is that these additional items must include the post name into the cart (such as main item ‘Sword’ and recommended item ‘Sheath for Sword’, with ‘Sword’ being the original post title).

The problem is that the single post templates are already being used, because people post comments, etc. So I was wondering if I am able to create duplicate single post templates for all the same existing posts?

Thanks in advance for your help!