Then you'll have to set up a new FCOS. Broadcast and delete.
I don't know the exact bits to enable, but you create a FCOS that uses the broadcast.
From there you go into the mail box you want to forward the messages from, assign the new FCOS.
Next go to List Maintenance and find the same mail box and in list 1 put in the mail box you want to dump to.
This should take all messages and dump them to what ever mailbox you want.
Ralph.