Long rests can be broken up by up to 1 hour of fighting or other stenuous activity and still count as a long rest. I could easily see keeping the short rest at an hour but allowing it to be broken up by fighting wandering monsters. They could still get the short rest bonus if the go straight back to finishing the short rest after the combat. Or you could put in a time limit of 5 or 10 minutes of strenuous activity is allowed in the short rest to bring it somewhat in line with the long rest's mechanics.