I am converting an existing site from OSC to Zen. My client uses an OSC contribution called 'Family Products'. The best way to describe this module is to quote the authors description:

Let's say you sell game consoles on your site...things like Playstation or X-Box. Well, you would probably want to show off certain products that would compliment your customer's purchase. For example, if they are looking at the Playstation 2 product_info.php page, you can create a family called "Playstation 2 Accessories" that consists of games, controllers, remote controls, and other misc stuff. Then when the user sees the main product they want to buy, you are "reminding" them that they will probably want to look the the other available complimentary products.

It is called Family Products because the idea was you would assign products into a "family" and that family would be called whenever a product was called that belongs to a family. In the example above, games for the Playstation 2 would also show when a customer is looking at Playstation 2 controllers, or any other product found in that "family."
I have been working with Advanced Cross Sell and while it is nice tool and sorta does what I want, the admin and client usage leaves a lot to be desired especially if you are looking a lot of products and "Families".

Is there anything close to this available for zencart?

tia

Rich