Highlight messages in the Inbox

Hi there,

We would like to highlight in the Inbox an employee survey email message that will be send out to the entire company so we can increase the number of people responding the survey.

We want to have a light touch solution, so something like using Mail Flow rules, but it looks like the best action available would be to amend the message subject.

I thought about using categorizations in Outlook and then adding a new Rule to each and every mailbox to apply a categorization to the incoming message and I would have to do that to each new mailbox that is created - it is doable but I would like something simpler to maintain.

Does anyone have other suggestions on how to achieve this?

Ps. We have Exchange 2016 Hydrid with Office 365.

Thank you,

Eduardo