Setting up a subdomain called www

Hello,
I have a site that has a few links pointing to www. www. mydomain.com. I've tried to set up a subdomain called "www" in cPanel but it's not allowing me to do so.
Does anyone know a work-around to this? Ideally I woud like to redirect www .www .mydomain.com to www.mydomain.com.
Thanks!

See original post by davidness