We have 2 separate phone systems a Tadiran Coral 3 with a uCmc Voicemail Card and a Cisco Callmanager System. These are linked together with T1 cards and extensions can call each other back and forth. The problem is when we have Tadiran voicemail trees that say if you know your parties extension please enter it now it only recognizes the tadiran extensions. How can I set it up so a voicemail tree will transfer to an external extension when it is entered in?