How do I properly wire in a generator start battery to an Orion 24/12 converter?

I’m running a 24 volt solar/inverter system with the VE Multiplus 3000 and 4 VE solar charge controllers and two battle born 24v LiFePo batteries and the Orion 24/12/70.

So far I’ve run my 12v system in the RV without the need for a 12v battery, but with the addition of a generator, I’m going to need more current to start it, so I’ll need to add a small 12v SLA/AGM battery to the circuit. Can I just splice it into the generator start wires close to the generator? Will the current try to skip the battery and just hit the Orion with its full 360 CCA ask and blow the internal fuses? Or is the battery the path of least resistance and I don’t need to worry about it? Or do I need to protect the Orion somehow?