Assign the lines to the Voice Mail calling group (770?) for immediate answer. Be sure to assign the lines to the individual auto attendants, option 6 in each AA.

Make the 0-out of the AA go to the appropiate operator extension, put the operator's extension in the voice mail coverage group, and make a mailbox for the operator extension. Unanswered calls to that extension will end up in that extension's mailbox (not the general mailbox), unless you use the "phantom mailbox" option to send them there.

Or, you could assign the appropiate auto attendant to each operator, and 0-out calls would ring the operator, and then go back to the AA.