Anyone use paypal shopping cart??

Knopfler

I have paypal shopping cart on my website (link below if you want to check it out), and it works great except for one thing. You can enter any quantity you want. I'm wondering if there is a way to limit it to the actual number of that card that I have, for example if I have 3 2007 Topps Heritage #1 David Ortiz cards, is there a way to not allow someone to enter quantity of 4 or more? Thanks.