Marine Battery Isolator for (2) Lifepo4 and (1) Agm Set

Hello! I currently have a Victron Energy Argofet 200A 3-Batt. FET Isolator, Auto 12/24V isolator for (3) Marine Dc31 Agm batteries on my boat that are being charged from a custom 180amp alternator. Since each of those agm batteries are only 110 AH I am considering swapping two out for (2) lifepo4 300 amp hour batteries. I have to keep one AGM battery for starting. My issue is I’m struggling to find a battery isolator that would properly charge the combination of these without burning my alternator up. Does anybody have any insight and what options I might be able to use? I greatly appreciate anyone’s help.

The lithium may charge fine from the alternator. I have seen people do it.

What you really need to look at is a DC DC charger connected to the AGM. The Orion Tr. The orion will charge the lithium when the AGM is full and regulate the current.