Background: To get round issues of branding our users have to send emails from specific domains that we own for specific products we sell. To make it more complicated all these email addresses come into the same mailbox. Lets call it Products. obviously the domains in this example aren't the real ones but lets say we own all the domain names I'm using.
So we have a products mailbox with a default address of products@marvel.example We also need to send and receive as products@dc.example And also products@darkhorse.example
To do this we have created contacts for products@darkhorse.example and products@dc.example and given the users send-as permissions for each contact.
We also have transport rules set up so any mail coming to either of the contacts is routed to the products@marvel.example account.
So from the user's perspective they only have to deal with 1 mailbox, and when they want to send as @dc or @darkhorse all they need to do is change it in the From drop down menu. This gets past the issue of only being able to send from your default address. It's not pretty or elegant but it works. It was all set up long before I joined, I just manage it now.
Problem: By default, the sent items go into the User's sent items folder. I can't redirect them to the contact sent items obviously because that doesn't exist. The user says it should be going to the products@marvel sent items whether they send as the mailbox or either of the contacts. I was convinced that wasn't possible, but one of the users showed me it working on their system. They send from the contact, and it goes into the shared mailbox sent items.
How is it working? They don't seem to have any rules set up. I can't see any transport rules that could possibly do it. Can anyone help me understand how it's working so I can replicate it on other people's systems?
To clarify: How can the user send as the products@dc.example contact, and have the email go into the sent items of the products@marvel.example shared mailbox?