I manage a large group of employees in our factory. Lots of the line employees are immigrants from Africa and work very hard. They do good work on the line and are highly productive. But too frequently, fights break out between employees. Last week a group of men broke into a yelling fight that stopped the line for several minutes. When I tried to get to the bottom of it, I was told the conflict was based on hatred between their countries of origin that had been going on for generations. What do I do? The fights are escalating.