The Sun Saver Duo already mentioned is one way to do it, it has connections for two battery banks. However, it will not handle nearly the current of a TriStar MPPT 60 if you need that much current handling capacity.
Another way to make this work is with a trick-L-start or amp-L-start. These would allow your house batteries, being charged by your TriStar, to also charge your chassis battery.
Or, you could simply use most any voltage controlled relay or automatic charging relay to combine the banks when the voltage is high enough to provide a charge and disconnect them when it's not.
