It's impossible as all the information they need (ie Nickname, display picture) are sent to all your contacts and that is how they know what your name and pic etc are.
When people "clone" you, it is just by using information Messenger retains about their contacts. It's not harmful in any way unless the pretend to be you and talk to someone you know for example. If this is the case and why you want to stop them, tell your contacts to check that it is your email address that shows up when you talk to them.
To be warned when one of your contacts clones you, you can use my script "Clone Warning" on the
scripts database
/ 
