Off Grid EV Charging

I am looking into charging an EV from our off grid supply in the future. The design goal is to prioritise the house battery charge over the EV battery. This would appear to require the use of an EV charger that can follow an external input.
In our case, the presence of additional solar supply capacity is indicated by the battery inverters adjusting the AC frequency, and ideally this would be used as a basis for dynamically setting the EV charger current.
I can determine the available additional supply capacity with my existing OEM equipment. Can anyone make recommendations for:

  1. How the EV Charger could be controlled, and
  2. Suitable EV Chargers available on the market that can be used in Australia?