Ok, You can try this. Test and see if it works.
Note: there is a reason you wont be able to find anything documented to do this by Microsoft and why the Out of Office only fires once per sender. Auto-Replies are a bad idea and can lead to mail loops or getting your org blocked.
Here is another example to try :
https://www.reddit.com/r/Office365/comments/93zvhm/office365_auto_reply_for_each_mail/
Once outlook loads, go to file->rules and alerts, then choose 'New Rule"
Click "Apply rule on messages I receive", then click next
Click next on the next screen, outlook will warn that it will send the message to ALL messages it receives, sounds like that's what you want, so click 'Yes'.
On the next screen, you want to select "Have server reply using a specific message", and "Forward to specific people or public groups"
Click on the 'specific message" link at the bottom, create your message template
Click on the 'People or public groups' link, and select the people or groups you'd like the message forwarded to
Click next and then finish