If you really want to trap your callers in voicemail jail, transfer the calls for finance to a hunt group with the finance extensions assigned to it. Overflow the finance group to another SEQUENTIAL group with only a single phantom user in to, and forward that user, including hunt group calls, to a short code that invokes the auto attendant. Prepare for angry, frustrated callers, who can't reach the finance department, and can't leave them a message to call back when they are available.