Cansbus Dual Chanel " listen-Edit-send"

this is my frist post here in arduino form i have learned alot form just reading topics other guys post here arduino is a brilliant idea .

back to the point i'm trying to build a canbus converter/modifier that has 2 canbuses like arduino due for example that can listen to the bus from CAN1 then edit only the msgs i choose before sending it back to CAN2 and all the msgs that i dont choose to change just forwarded as is from CAN1 directly to CAN2
my programing skills is not that good so i need help on how i can implement this idea into a code

this project will be used in a VW jetta where i want to install VW DSG gearbox to a manual vichle so i need to modify the canbus for the jetta to make the DSG understan it

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