No email sound for non-default mail folders

[SCLEng]

We use a network that has other email address folders in the main mailbox.
When email is forwarded to them from the main mailbox or is
addressed/received directly to them, we can't figure out how to get an alert
by either a desktop alert or by a sound. Any way around this? I tried
creating a new rule but can't get the sound to play after the email is
transferred or received on their computer instead of in the "owner" computer.

Thank you.
SCLEng