Alternator and LiFePo battery question

The wire from the alternator to the batteries and from the house battery to the inverter is all 1/0 ga. The very short wires from the batteries to the DC to DC charger are 6 ga as specified by Redarc. The problem is the alternator is tied directly to the house battery. This is so it can be used as a boost if the starting battery is too weak to start the engine. I need to disconnect the alternator from the house battery so it only feeds the starting battery, then passes through the DC to DC charger to the house battery
I will miss the super fast 80-100 amp charging lol, but I don't want to risk burning out the alternator.