Paypal Standard configuration and how to manage multi stores

Good morning,

We urgently need to understand how to manage multi-site payments with a single PayPal account (different e-commerce on different domains). The doubt arises from the fact that updating PayPal's "website payment preferences" only allows me to add one return URL, while I would need two different ones. We don't want the user who purchases on site A to be redirected to site B or vice versa. I am using the PayPal Standard plugin, and the NopCommerce version is 4.30.