Web server virtual filenames

I am not sure whether this is possible. I need to upload 1 file to web server. Then download this file as multiple parts/chunks with fixed size. In other words, after request for download of http://ift.tt/2x4Ue8n, the web server has to run some script and give it the URL or only 123 as parameter. The same is possible with: http://ift.tt/2vEMlD0 - then index.php or index.aspx will return chunk #123. Can the same be done with dir/file123.bin syntax?