I am documenting this here as it was not apparent when researching this and took a while to find, hopefully this will make the answer more obvious for anyone needing it
If you want to server content from one domain on another domain, this can be achieved using mod_rewrite rules in Apache. This is done by using the [P] flag which enabled mod_rewrite to pass urls through to mod_proxy to another server.
The following example will pipe all traffic from www.example1.com/example/ to www.example2.com
RewriteEngine On RewriteRule ^/?exmaple/(.*)$ http://www.example2.com/$1 [P]