Site A: Cisco CM 4.2 (212-555-75XX)
Site B: Nortel 81C (212-555-79XX)
Site C: AVAYA (305-666-45XX)
Site A and B are in the same building, connected via PRI link, routing plan had been configured, user can dial to each other directly by 4 digits extension (75XX and 79XX)
Site A and C have IP connection already, recently, we use voice gateway to connect Site A and C, and configured all site A, B and C.
When Site A user dials 9-1-305-666-45XX, CM will route the call via voice gateway to site C. (Done)
When Site B user dials 9-1-305-666-45XX, Nortel will route the call to CM, and CM will dump all digits to site C via gateway. (Done)
When site C user dials 9-1-212-555-75XX, AVAYA will route the call to site A and dump all 10 digits to Cisco CM. (Done)
When site C user dials 9-1-212-555-79XX, AVAYA will dump all digits to Cisco CM and CM will route it to Nortel. (Failed, fast busy tone on site C)
79XX configured as route pattern in CM. Gateway transmitted all 10 digits number from site C; it may work for site A Cisco CM, but can't recognize by Nortel.
How to configure the Cisco CM or Gateway to only transmit last 4 digits (79XX) to Nortel when received 212-555-79XX from site C?
I appreciate your help!