On-Premise Organization - Single Forest (Exchange 2010)
Parent Domain: contoso.com
Child Domain: child.contoso.com
Cloud 365 Tenants
Tenant 1: contoso.onmicrosoft.com (dirsyncs with parent domain)
Tenant 2: child.contoso.onmicrosoft.com (dirsyncs with child domain)
An Email needs to be sent
From: email@example.com (this mailbox is in Tenant 1)
Distribution Group (notice this Distribution Group lives in the Parent domain but can be on premise or in cloud)
How can we achieve this? This has been done before but now I cannot figure out how they accomplished it.
Nothing is off limits... SendAs/Full Access permission - whatever you want to use to accomplish the above solution is fine.
Thank you for your time in advance!