Multisites on sub domains

Apologies if this is very elementary, but is it possible to manage multiple sites in WordPress using sub domains? What I’d like to set up is something along the lines of http://anz.mycompany.org or http://northamerica.mycompany.org – as you can see they would be regional sites that would need to be linked and share common content and look and feel, but have a separate navigation menu.

Thanks for any advice!