Perhaps all that is needed is a resolution to approve charging at up to 15A from each unit’s individual supply with the addition of a 15A socket or a wall-mounted EVSE outlet limited to 15A in each unit’s parking space with all repair and maintenance the responsibility of the relevant unit owner.
AS3000 rules say that 15A sockets are supposed to be on their own circuits. So in this situation, you should have a switchboard in each parking space, one breaker for the 15A socket and another breaker for everything else.
Not hard to include two breakers when splitting the 20A supply between a 15A socket (or hard-wired EVSE set to 15A) and the lights.