I managed to suss out some of the bus messages on vehicle can busses, its fairly complicated, and diffrent manufacts are not the same.
I didnt quite get what you meant, if there allready is a monitor on the bridge you might be able to tap into the serial comms lines and listen to whats going onm then suss out the protocol, the display probably works in a similar way to vehicle can systems where you send a request and the relavent controller replies, or possibly mtu being a larger manufacturer the system might use arinc, this seems to be popular on bigger stuff.
Once you have an idea what the request strings are you could try connecting to the engine control with a serial terminal package like putty.
All this is assuming you have the skills to write your own code/build something.
If the protocol is simple you might be lucky and get something like torque to work, its a android based dashboard system that works with obd, you can add custom guages and setup request messages, it works with an elm 327 interface which supports a few can protocols, you might be able to wire it in if the engine control uses one of its supported protocols.