Mail Flow for terminated employees redirected to a public folder - cannot get employee's out of office message to trigger

Hello,

I have a few employees who have been terminated.  I have their mailboxes set with a mail flow rule to redirect to a public folder, so that we can see messages that were sent to the employees so we can respond to them.

However, with this redirect rule in place for each mailbox, their Out of Office message isn't triggering - the message that would tell a sender that the employee is no longer with the company.  Ideally, senders would be notified that the employee is not there now.

Is there a way to set up a message to be sent to any senders trying to email a mailbox, while still having funtional mail flow redirection?