Viewing Email Aliases in New Outlook

Hey everyone, I work for my company's IT department and we got a request from a user that wanted to know how to view aliases for an email recipient's outbox. All of our emails display as:

firstname . lastname @ campus . edu.

In the Old Outlook this user was able to right click on the recipient's name and go to Outlook Properties and in the first box there was an alias section that showed their username, which is what we all use to sign into our accounts. Is this not possible on the New Outlook or merely under development? Thanks!