We already have an apple pay integration with a psp.
We have a merchant id with an identity certificate, a processing certificate and merchant domains. We are working to integrate an other psp. This psp have one csr (processing certificate) by customer. All the payment will be processed on the same domain. We have understood that it is not possible to have different processing certificates for a merchant id. So we can not reused our existing merchant id.

 On the other hand, it seems that it is not possible to have different merchant ids on the same domain (because of the domain verification). But all payments are processed on the same domain.

 Do you think there is a solution ?
Is there a recommended workaround for this scenario?