Maybe this old topic is interesting for you.
For the rest I hope that one day Victron might come up with an external relay module, just like they more or less did with the GX Tank 140. More relays means than you can control more in your boat, or RV, with an additional GX Touch display, like turning on/off lights, pumps, etc. And in your case, also the option to add the relay module to certain (extra) If-Then rules.