Only allowing certain customers to see certain items

I am setting up Zen Cart for a customer in the printing business. All of the products my client is selling are custom to specific customers. In some cases a product will be specific to one customer, in some case to a few customers, but none of the products will be available to all customers.

I need to figure out a way to limit which customers can see which products in Zen Cart. I have already changed the settings so that customers need to be signed into see any products. I need to go further with that so that when a customer signs in he will only see the products relevant to him, and no others.

Please feel free to ask any questions if they will help clarify the issue. Thank you in advance for your help!

--jack

After much searching and testing, I think I am closer to solving this, and my question is now more focused.

Is it possible to limit a customer to seeing only one category?

Thanks!
--jack