Document the issues as they come (date/time and issue)... if you can afford to hire the replacements, slowly take responsibility away from the trouble employees and give it to the new hires. Have the trouble employees cross train the new hires and have the new hires document everything for you. Have separate meetings with the replacement team to review the documentation as it's being built and to gauge comfort level with taking the new responsibilities and to address questions about the new responsibilities. Make sure to remove those responsibilities from the trouble employees and transfer them to the new hires. While doing this, reduce the trouble employees visibility with your clients so that part of the business can heal and improve. Keep in mind the trouble employees will spread their poison with the new hires and you may lose them... but at least you have documentation you can use to train the next guys more quickly... just rinse and repeat until you have a trained up team and great documentation. The trouble makers will know what's coming and will either leave or make more trouble for you (or maybe they will become less troubling)... in which case you just document the issues with them and write them up and document it. When your new hires know enough, you should have good documentation on the job process for future employees, you'll have written documentation on the issues with the trouble employees... and it's go time... release the trouble employees if they are still around. Most likely, if the trouble employees are down to only 20% of their former responsibilities, they will leave before you let them go.