Load Balanced Web Servers (upload issues)

To better ask this question, you must know the existing configuration of the architecture first.

We have a very redundant environment with multiple load-balancers and firewalls, etc.

We have a back-end repository where files are stored in a big array and the front-end webservers rsync content from this back-end repository overwriting any changes made locally on the webservers.

The database is replicated using the mysql replication to another server as well, but until a failure happens, the front-end webservers know only of the primary database server. Regardless…

I noticed the upload option: Options–>Misc in the admin interface which defaults to “wp-content/uploads”.

I am able to “write” to the back-end repository server using an internal IP, etc. and can setup a host called something like “admin.domain.com” and have it resolve to the internal repository IP to post images and uploads to so that it will replicate to all the web servers, but WP will redirect back to the main WordPress address (URL) as defined in the Options area when I try and use a hostname (non-www.domain.com).

For example, the main website is: www.domain.com. My “admin” area, I want to setup is admin.domain.com (which resolves to an internal IP pointing to the repository)

When I do it this way, it just redirects back to the main https://www.domain.com area.

So my question is:

Q: How do I do this so that just I (we) can update the blog with images/attachments to a host that is not defined in the primary options area.

(Other than just creating an “image.domain.com” host and hard-linking by the way)

Any help is appreciated.

Thanks!