Thanks again for working on this

I haven't yet tested the functionality thoroughly, but I took a look at the product node options and action. One issue I see is that it is a blanket group setting for the product, rather than the SKU. For example, for File Download, it is a "Feature" added to the product, under which you can choose the specific SKU (or all SKUs) that it applies to. This allows you to have different SKUs for different attributes, which could affect the desired group membership. I would think this feature makes sense as a product "Feature" that behaves in the same way as product file downloads.