Pre-LP Gallardo off road tune to eliminate rear O2 sensors

First time post from a new Gallardo owner: I'm prepping a 2004 Gallardo for some SCCA national autocross and time trials events and have built a lightweight custom exhaust that does not have provisions for the rear O2 sensors. Is there a tune for this car that can suppress all codes from the rear O2 sensors when they are disconnected?

Some background - several weeks ago I purchased an "off road" tune from Vivid Racing and the short story is that the check engine light is still on from P0137/157 codes with rear O2 sensors attached but strapped up inside the engine compartment. If the sensors are removed P0141/161 codes are present for the heater circuit not complete. I've prepped numerous cars over the years and removed the rear O2 sensors and was able to suppress the codes without simulators, etc.

Thanks!