And you can’t control others, they get to make their own decisions. If it’s a campus level problem, then your principal has to handle it. If it’s within your program and your district is is set up in a way that it’s your responsibility, then by all means set up the PD for your department. Then you start holding people accountable for their actions with lots of follow up meetings and documentation. Your staff has to know that this behavior is unacceptable. You’ll have to have your admin on your side though as you begin documenting conversations and directives, especially if it’s leading to a negative employment outcome.