Custom Sub-domains

Being able to have custom domain names for our collectiveX community is great, but what I'd also love to be able to do, is associate a subdomain with a collectiveX community.

Is there any chance there might be a simple way of doing that??

For example, we have a website at http://growsouthafrica.org and we want for the community to be at http://community.growsouthafrica.org as opposed to using http://growsouthafrica.org for the entire online community.