Set minimum quantity for a product

I'm setting up a shopping cart for a a wholesaler, and he needs to be able to set a minimum quantity for each individual item (these items are sold only in bulk). Is there any way to do this?

It should allow the user to add the items to the cart only if a large enough quantity is selected, and then allow them to checkout only if a large enough quantity has been added to the cart.

I've seen this post, but that only explains how to set the minimum quantity for the total of ALL products. http://forum.opencart.com/viewtopic.php ... ity#p24609

Any ideas?

Thanks a lot!