No. Currently subdomains may reference only a main directory (www.yourdomain.com) or a subdirectory one level down (www.yourdomain.com/subdirectory1/). You cannot assign a subdomain to a subdirectory within a subdirectory (www.yourdomain.com/subdirectory1/subdirectory2/).

Please note as well that you can point a subdomain only to a Yahoo!-hosted web site. You cannot create a subdomain that sends your visitors to a site hosted elsewhere.