Office 365 is such as huge platform that you are always learning new stuff day by day. This time, after being asked by a customer, I’m showing you how easily you can move message between Office 365 Groups by using Outlook interface in your browser:
First thing you have to do is just add the source and destination Groups in Outlook so you can manage them as regular MailBoxes:
Then, to move messages between the Groups you have two options. First option is just to select the messages to be moved in the source Group and just drop into the destination Group:
As a result, you will see the messages you have just moved in the destination Group:
Second option is just to use the Move action in Outlook:
Important Note: Please, note this approach to move messages between Office 365 Groups is not officially supported by the Office Groups Teams. I have been advised about this fat by Ethan Li, Program Manager at the Office 365 Groups Team. The team is currently working on a way to provide drag & drop capabilities in Outlook on the desktop, but there are no timelines to share at this point.