Automatic case update email from user email address

We support multiple brands. I would like to send automated emails with notes from case updates to the contact associated with the case.  I have done this with both Workflows and Process Definitions but both only offer the option to send from the 1 system email address.  I would like to send from the User email address assigned to the case.

I tried to make an email template and pull this in manually to an email created from the case but the scripted fields did not populate correctly.

Does anyone have an idea of how to accomplish this or if it is possible?

Thank you,
Bob