Multiple owners corporations and single gas meter

Context:  a pretty common Victorian multiple OC setup for a property that is mixed use – Every owner belongs to two of the three OCs (OC-shared+OC-residential for residential, OC-shared+OC-commercial for commercial).  There is a single gas meter for the whole property.  The same strata manager looks after all three OCs.

For many years, OC-residential (residential only) was paying 100% of the gas charges for the entire complex.  A number of years ago, the OC-shared committee undertook a sustainability audit which uncovered that a very significant majority (>80%) of the gas used was by commercial tenants (a number of restaurants) with their kitchens who were paying precisely zero for gas up to that time.

Since then, all gas billing now goes directly to OC-commercial (commercial only) to try and make up for lost time, but that does not correct the incorrect billing to OC-residential (residential only) from the past.  It’s probably too far gone now anyway to fix to be honest.  COVID has meant that the commercial lots are in financial distress in any case.

But I will pose the hypothetical anyway.  I am interested to know if anyone has experience with shared gas meters particularly across multiple owner corporation sites and what successful strategies they have had to deal with them.