Hi tom,
for us at tvnoir.de/crowd it was quite a pain du be restricted to alternatives of ONE product for one campaign. MUCH better would be to declare one or more campaigns (e.g. by assigning them to a category “crowdfunding-campaign-fall-2016”), and then you can flag any product and/or variation to “contribute to that campaign”, e.g. by assigning that category. If you in fact use the concept of categories, then also summarizing all products that contribute to the campaign is already implemented…
thanks, tex
