Strictly speaking they need to stay at a temperature above 140F the whole time. Can you put them in a very low oven or slow cooker to stay warm (but not overcook)?

Wrap the dutch oven in a few towels and put it in your oven (turned off of course). As long as the beans are hot when you put in in there it should stay at a safe temperature for several hours.

What liquid did you use? Beans are not a PHF (Potentially Hazardous Food), so Time/Temperature controls aren't hugely important. It's always BEST to avoid the Danger Zone (41 - 140) but even PHF's can be in the zone for 1 hour, according to federal food handling procedures. If you used water to cook the beans, you shouldn't have a problem.

ServSafe Food Manager Certified btw :)

Begging to differ, any food if cooled improperly runs the risk of becoming a PHF. Time & temperature abuses are the most common source of food-borne illnesses. Two hours are allowed to reduce a food's temperature to 70 degrees or below, then another 4 hours to reduce it to 40 degrees or below. Beans are extremely dense and require some attention and effort to cool under perfect conditions. Several hours at room temperature will not accomplish either of those. People's advice to keep the pot hot is quite accurate if cooling objectives cannot be met.

ServSafe certified instructor ;0)