Version: Zen Cart 1.3.8a
URL: http://www.electricdreams.com/Shop/

I have been searching but haven't found an answer for this.

In this store, the owner would like the ability to add to cart if quantity is 0. This is how it is currently set up.

However, here's the problem: He also sells 1 of a kind items - so those can't be sold if the quantity is 0

Is there a way to select products to allow backorder/preorder and which don't?

Thanks in advance!