Do you have anything on the above, or work rules regarding supervisors and people that report to them having a friendship outside of work. It is becoming disruptive to the workplace.
I think anti-fraternization policies are really difficult to write and police. How do you get people to stop being friends? And if you don’t want supervisers to be friends with their underlings, then you can’t promote from within, or you have to say, “If we promote you, you won’t be able to socialize with the people you used to socialize with.” Except you’d say it with better grammar.
What you are in need of is some supervisors with a clearer understanding of what is expected of them. You need to manage the results. You need to talk to the supervisors about how favoritism (presumably that’s the problem here) is affecting the entire team. You need to train your supervisors how to manage.
Very few companies actually do that. Heaven knows my management training was weak. (New boss: “Hey, here are some people to supervise!” Me (outloud): “Great. I truly believe I have a lot to share and I am looking forward to taking this next step in my career.” Me (silently): “Crud. I’ve never even had a formal performance review. Now what?”)
I wouldn’t focus on the friendship part. I would focus on the measurable results part. Make sure that your supervisors have good managers who have set quantitative goals for them. Make sure they understand that they need to change whatever behavior is causing the problem.
If they can’t do it, they should be removed from their supervisor positions, either through demotions or firing. The latter is probably perferable, because if you’ve got anxiety in the ranks now, putting a disgruntled supervisor back in with his former underlings will not be pleasant.
Part of the job of managing people is realizing that you get paid more because it is harder than it looks. This sometimes means changing your relationships with others. Focus on the results and the relationship problems will be solved.