If you have currently configured a single tomcat server and you need to add more tomcat servers, first remove the CATALINA_HOST environmental variable.
The configure more tomcat servers in new ports. (How to change the Tomcat running port)
Now go to Command Line.
Go to the first tomcat server directory through command line and go to bin directory.
Type "startup" and execute Tomcat.
Then your tomcat server will start.
Now go to the next Tomcat server dirctory through cmd and as same as the first one execute it through command line.
Here as we haven't created CATALINA_HOME variable , we can not execute Tomcat straghtly double clicking startup.bat file. So when we execute Tomcat from cmd, it creates required environmental variables at that time and starts tomcat.