Ah! I finally understand the connection. If you literally take multiple ground leads from the battery, one of the ground leads would be bypassing the shunt making it useless. I don't think that was the intent, at least not mine.
After all this conversation, I'm leaning towards a negative bus in the battery compartment acting as the main DC ground bus where the batteries, dc distribution panel, & 24 hr circuit negatives are connected. This will also be where each negative post of the battery banks will terminate (eventually through a BM shunt on the house side). The main negative bus will be connected to another bus in the engine compartment acting as the main ground bus wich will be connected to the starter ear (to provide minimal voltage drop to the starter) and to the B- part of the alternator (to provide more efficient charging) . The ground bus is where the ac ground and all other ground wires will land.
I understand the ground bus will technically add resistance and an additional connection, but the benefit of not having a ton of cables connected to the engine as well as the starter and/or alternator not having to rely on the block for their return path outweighs the negative. I'll even get to add a battery monitor like the Victron on Luffalee (although the Balmar looks intriguing).
This configuration should get all the connections off the exhaust elbow, clean up the negative terminals of the batteries, provide the single return where I can insert a BM shunt, and reduce voltage loss on the starting and charging circuits. Now I just have to dust off the cable sizing calculator and get to work.