If it were me, I would just plug the MH into the available power using whatever adapters are needed. The converter or inverter/charger (depending in what your Meridian has) will keep your six house batteries charged. Check your manuals and see how your chassis batteries get charged from shore power. If they receive nothing from shore power, you need to get an
Amp L Start that will charge the chassis batteries by providing a bridge from the house batteries whenever the chassis batteries drop below the house battery charge allowing your charging source to charge both banks. A battery minder/tender is a very low amperage device and will not do what you need.