Adding CRM Online to Relay on Exchange 2013 + Office365 = Hybrid setup

hi all, 

I have CRM Online (SAAS) 
I have exchange 2013 On-Prem + O365 = Hybrid setup
I want CRM Online to send email's using Exchange
Source = CRM Online 
Destination = Exchange Server

usually for such situation i used to add the application server to relay on exchange
In this scenario my source = CRM Online (Saas) - When i asked the vendor details of source server he mentioned they might be multiple IP's as its SAAS

Is there anyway to allow CRM Online to send emails to Exchange

The CRM Online + Office 365 are on the same subscription

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tfernandes