Adding related products feature to product

It would be handy if there could be a feature where we can link products to related products (i.e. if a certain product is needed to make something or complements another product but are sold separately then they could be linked within Storefeeder). This would be very handy for using on Shopify as otherwise we have to create a separate list of related products when this could be done in one hit on Storefeeder ready to download and add to Shopify.