Site and User Registration on a Subdomain

I’m wanting my users for the entire network to register and create new sites from a subdomain, as opposed to, the root.

I should note, BuddyPress is only installed on the subdomain, which is part of why I’m directing network wide user registration and site creation to that specific domain.

The issue I’m experiencing in using this setup, is that the new sites that are created, become a subdomain of the subdomain “usersite.subdomain.mysite.com,” when what I want is “usersite.mysite.com.”

Does anyone have any insight as to how I might achieve this desired result? I’d greatly appreciate it.

I thought the multi-domains plugin might do the trick, but at the same time, it seems redundant adding a wildcard to the wildcard that already exists, and I’m not even sure if that would work.

Also, in the BuddyPress register.php file I thought I might find some insight there, but it seems to treat the home_url as the subdomain where it is installed.

<?php echo home_url( '/' ); ?> <input type="text" name="signup_blog_url" id="signup_blog_url" value="<?php bp_signup_blog_url_value(); ?>" />
<?php endif; ?>

Thanks in advance for anyone that has anything to share.