My first step would be to figure out HOW the calls are forwarding. While one is forwarding, run the status station XXXX command. If there is something in the CF Destination field, then it's call forwarding. If it's blank, it's probably a coverage path.
If it's call forwarding (I doubt it if it's automatic):
Or you could use telecommuter. See what DID # is assigned to telecommuter (change tele).
Then you dial in and do the following:
1) Hear Dialtone : Dial FAC for EXTENDED CALL FORWARDING disable
2) Enter the extension you wish to disable, then press #.
3) Enter the stations passcode, then press #. (The passcode is setup on page one of the station form).
4) You should hear three beeps. It's now turned off.
If the CF Destination field is blank:
I'd also check the actual stations themselves..what is the coverage path?
If it starts with a T, you're using time of day coverage paths. To modify where the call routes, use change cov time X. You'll see a schedule which shows what coverage paths are activated at what times.
My guess is you are more than likely using time of day coverage...
SJF