Set fax availability hours?

Is there a way on a WorkCentre 7855 to set the hours of availability for a fax machine?

I'd be satisfied with just disabling the fax line outside of business hours (so faxed credit card numbers aren't sitting on the machine when the overnight cleaning crew comes through).

Forwarding to another fax number outside of office hours would also work, if that's available.

I've read through the documentation on fax forwarding, but can't seem to find anything on this.