Paypal Multiple Auto Return Urls

Hi, I have several different and separate websites but I use the same PayPal Business account for all of them.
Is it possible to set up Auto Return with Payment Data Transfer activated for each of my sites? I only see one Auto Return field under Website Payment Preferences. I don't want to set it up for site A and then customers from site B and site C get auto-returned to site A after their transaction. How can I set this up so that upon checkout customers are auto-returned to that specific site that they came from and I receive an IPN from that site's transaction? Thanks!

Maybe this works

nopCommerce automatically handles this subject
by fill return url field on paypal form
no need to add anything
just fill "Business Email" and "PTI Identity Token" on "Edit payment method"

            string returnURL = CommonHelper.GetStoreLocation(false) + "PaypalPDTHandler.aspx";
            string cancel_returnURL = CommonHelper.GetStoreLocation(false) + "PaypalCancel.aspx";