cross-site Coupon

We are trying to create promotional codes at the request of different shops or companies (different sites, developed in woocommerce) and they will be consumed in different businesses associated with those companies or shops. We already have the code generator, but we are wondering if there is a way to make that coupons work in multiple sites (i dont know if connecting via api).
Any ideas for that?

Thank you!

The page I need help with: [log in to see the link]