simulated vhosts

i know now that you can't use the <virtualhosts> directive in .htaccess. problem is that i need to! hehe... so what i'm doing is allowing some of my friends a little webspace on my domain. unfortunately i don't have rights to the httpd.conf so consequently i'm unable to setup vhosts. so i'm wondering if there's a way i can do this via php or better. here's the structure i wanted to do.

lets say i gave "braindead" space. ideally i'd like him to have a subdomain, braindead.mydomain.com which points to /var/www/users/braindead to keep my root directory nice and tidy. now given - i CAN create subdomains with my host... unfortunately when i create a subdomain in order for it to work the structure would need to be /var/www/braindead (which totally undermines my idea of tidyness)

so voila there you have it. my problem. any solutions/suggestions are certainly welcome.

No, You need to be able to set the virtual host directive to do that.