Need to modify/filter a signal in a CAN bus.. picture inside

[iso9001]

Hi,

I've been working with CAN a little bit and come across a problem where like the subject says I need to take a specific couple of signals from a CAN network that is already in place (DeviceNet between two machines) and modify just those signals. Dual wire, High speed. These are big complicated machines so remaking them or reprogramming is not an option.

I am aware that there is the possiblity of an arbitration error occuring if both A and B start at similar times but I think this will be minor.

Any ideas ?