I have a 3845 with 2 ISDN PRA interfaces running as a PSTN gateway. Customers running various PBX systems connecting to this gateway via SIP trunks. I want certain calls from a specific customer go outof a specific PRA. I achieve this by checking 'calling-number' with the 'answer-address' command. But problems arise when the calling numbers are not presented correctly as calls will go out the wrong PRA interface. Is there a way to check both calling-number and source IP address to route the calls?