Changing the Upload folder path to dedicated folder

I put wordpress running on a cluster of servers where the I need to specify that the images get uploaded to another server. Currently they are being stored at /home/www/mydomain.com/public_support/wp-content/ but I need them written to /home/www/mydomain.com/public_files/support/wp-content/. And then instead of the images being called from http://www.mydomain.com/support/wp-content/uploads/2014/12/image.jpg I need them called from http://files.mydomain.com/support/wp-content/uploads/2014/12/image.jpg