You need a new approach than just heavy handed discipline plain and simple. It seems that this is what you do and there is no changing that. I would start reading some books on behavior management and start implementing them NOW. Take a week off to read and start monday morning with your new tactics. Ask for book recommendations from people on here who have dealt with issues and came out the other side using a new approach. I wouldn't be able to do what I do without the books I've read.
It doesn't matter who you get rid of, this process will continue to repeat itself without a discipline plan other than what you're doing. Sorry that is how I feel
