Sent Items saved into Shared Mailbox Sent Items folder
What Group Policy changes need to be made to make Emails sent from a shared mailbox be saved in the sent items folder of that shared mailbox instead of in the users sent items folder?
Our environment consists of Windows 7 and Windows 10 computers, using Office 2016 x32.
Just remove shared mailbox from "Additional Mailboxes" for your Exchange account and add it as a separate, second Exchange account.
Qlemo
+1 for Alexei's recommendation. You can use more than one Exchange account since Outlook 2010, and should do so.
Qlemo
Interesting that you decided to accept the answer two Experts were telling not to use ... This is really a bad idea. The mail is stored twice, using a shared mailbox in "Additional Mailboxes" has many disadvantages, and you really should use the feature of multiple Exchange accounts with Outlook 2010+.