Yes. Many here use a True battery isolator . . . it's really a management system. It will allow a charging source for either battery to also charge the other battery once the battery being charged reaches 13.3 volts or so. When discharging one battery, it will allow the other battery to "help out" but will not allow the battery helping to drop below 12.8 volts.
As an example, if you are winching with engine off, as circumstance won't allow you to run engine, the aux battery (usually primary for the winch) will run the winch but the main battery will help out until it's voltage drops to 12.8. Thus reserving power to start the engine later.
Disclaimer, I'm getting old, so stated voltages may not be exact, but you get the idea.