System is CICS with 7.0. No Call Pilot. Lines are POTS.

For those times when there is only one person in the office and they are on the phone, the customer wants any additional calls to be sent to an external phone number.

Call Forward NA only forwards to an internal number.
Line Redirection works, but forwards the incoming call immediately. They would like a 4 ring delay so they have a chance to answer. After 4 rings it should go to the external number.

Any other way to do this?

Thank you.
Jim