Software Update Point Component Properties - Products (tab)
Add a hidden process that will detect every product in the list on each device (with every hardware inventory).
Add a "minimum threshold" value which is the minimum number of detections necessary to auto enable a given product in the list.
on a schedule (weekly) re-evaluate the status of this product list.
The detection mechanism can be a monthly update package (which is ALWAYS enabled) .. it simply logs the information in the device registry.. Hardware inventory can them be targeted to collect this information.
Here's an article on how to manually setup SCCM to get a report on which products to select.
How to Identify Which Products to Select on the SUP/WSUS Products tab
https://www.scottjfairchild.com/blog/20/how-to-identify-which-products-to-select-on-the-sup-wsus-products-tab
It would be really nice if WSUS could automatically add\remove the wsus products lists.