This post covers how to add an alias address to a distribution group in Office 365 using Powershell. The email address is added by using the Set-DistributionGroup cmdlet, but the PowerShell code you need will be created for you by filling out the form below:
Copy and paste the text above into a PowerShell Window and all the hard work will be done for you.
You will be prompted for your Office 365 credentials (make sure you enter credentials with permissions to edit the group) and then then your session will be established. You should get output similar to this:
Hope this helps 🙂