Connect two on-premise CRM to one Exchange online

Hi, we have two on-premise Dynamics 365 environments (on in the Netherlands, the other in China) and we share one Exchange online (both have different domains and a user is connected to only one of the two domains).

Our D365 in the Netherlands is connected to Exchange Online and now we also want to connect our on-premise in China to this same Exchange.

Does anybody have experience with this, or maybe have some kind of white paper to configure this?

Best regards, Jos