Hi Apple Pay Team, We are building a QR-based payment platform and planning to integrate Apple Pay on the Web as a Payment Platform Integrator. Our setup: We operate a single domain (e.g., pay.example.com) where all Apple Pay transactions take place When a customer scans a merchant's QR code, our hosted page opens with the Apple Pay button We process payments on behalf of multiple merchants (receivers), each with a separate merchant ID at our payment processor We want to use a single Payment Platform Integrator ID with one set of certificates (Merchant Identity + Payment Processing) The payment processor handles sub-merchant identification and settlement to the correct receiver via card network (Visa/Mastercard) sub-merchant fields Our question: Since all transactions happen on our single domain, is it mandatory to register each sub-merchant via the Apple Pay Web Merchant Registration API (/paymentservices/registerMerchant) and use their partnerInternalMerchantIdentifier in the payment session request? Or is it acceptable to use our Platform Integrator's own merchant identifier for all payment sessions, given that: Only one domain is involved Sub-merchant identification is handled at the payment processor / card network level Our domain verification file is already hosted and verified We would appreciate clarity on the correct approach before we proceed with our integration. Thank you.