Reciprocal Cross-Selling in WooCommerce
Often time you may carry a new product that is specifically suited or designed to go with another product. As it stands now, you would have to make each product a cross-sell of the other. It would be nice to have the option of automatically making a cross-sell reciprocal.
Have you checked out WooCommerce Product Recommendations?
The extension allows you to create recommendation engines to accomplish what you describe, for example have a look at this "Complete the Look" example: https://docs.woocommerce.com/document/product-recommendations/recommendation-strategies/offer-complete-the-look-recommendations/
You can read more about it at https://woocommerce.com/products/product-recommendations/
Just to be clear, this is for a single product. A one to one relationship.