I have a site that I want to have a couple pages be accessible via a subdomain.

Site: xyz.com

I want to have blog.xyz.com and support.xyz.com.

I want blog and support to be subfolders in the main site and have the same templates and everything. I know I can do all this with a domain alias and point it to that sub directory.

My question is: Is there a way to use a css list menu so the links for all the other pages always link back to the main domain even if you're on one of the sub domains?

When I tried setting it up, if I browsed to blog.xyz.com all the links in the menu would then be blog.xyz.com/page1, blog.xyz.com/page2, etc...

On top of having the menu link to the main domain I also don't want those other pages to even be accessible from the subdomain. So if the user were to browse to blog.xyz.com/page1 it would redirect them to the main domain or at worst throw a 404.

Thanks.