Pre-Requisites?

Hi there,

I've looked and haven't found how to do this...

For this website, we would like to have a standard Hikashop feature or one accessible via a plugin
NOT via editing of Views [we want to avoid this at all costs so that we can upgrade the site as new version of Hikashop come out
in the easiest way possible] which does this:

We sell courses/lessons/classes - for that we need to be able to have a - you can buy this class ONLY if you have already bought this class.
[otherwise known as a pre-requisite].

Ideally this functionality would be at the product page level in a similar way as Related Products.
[possible terminology of this feature: Pre-Requisite or Required product]

Let me know,
Thanks,

Emmanuel.