We have a shared mailbox on Exchange 2010 that multiple clients access using Outlook 2010. There are multiple distribution lists (that each have multiple email addresses) that point to this single shared mailbox. This was done to enable server-side processing rules to place messages into specific sub-folders depending on the email address that the message was sent to. For a (slightly) more visual example...
Email sent to vendor1@domain.com (Vendor 1 Distro) -> Shared Mailbox -> "Vendor 1 Folder"
At the moment, if a user clicks Reply, the From address is sharedmailbox@domain.com. The user can manually change this to vendor1@domain.com and it will send without issue (Send-As granted ). What I would like is for the From address to automatically default to the email address that the message was originally sent to. Is this possible without some custom Outlook extension?