Hope this feature will be added soon. We use EasyBlog and implementing load balancer. In a load balancer implementation, all uploads required in external disk so it will be loaded across all server instances.
Maybe you can try to test them out and see how it goes. Do remember to test them by cloning your site or using your Test site so that if there are issues, your live site wont affected.
If you got any issues, dont hesitate to report them by creating us a new thread instead. I will close this thread for now. Thanks for your understanding.