I'm having one client who has a special requirement, i have setup FS for them using static XML files and a GSM dongle, they are able to call other extensions and gateways as well as dial out of the GSM line but they wanted incoming calls from GSM to ring the extension that called the person using the GSM line. Meaning extension 1008 calls a number which FS routes out of the GSM line so the called party sees the GSM number always and suppose if the called party is busy and doesn't answer or rejects call then when later he dials back in I want FS to know which extension had called that number so incoming calls from the GSM would ring that extension only. I know I can do this dynamically using XML curl and CDR etc but is there a simple way to achieve this using static XML files only as this FS setup is very small and very basic