I am the boss of the company! I have a finance, a sales, and two directors are at odds. They are both veterans of my father! What should I do?

Ask them out, have dinner to communicate, solve the misunderstanding, and say that we should work together to improve the company's performance and expand our business. This is our goal. They'll realize. The development of the company depends on your parents, and both are indispensable. Hold them high and they will work harder.