No, there isn't. Although the page in the iframe is visible inside the other page, they are in fact separate windows. The concept of separate windows is handled entirely by the browser, the server is not at all aware of the relation between the windows in the browser. What is sent to the server is just a request for a page, there is no information of where (or even if) the page will be displayed. The server just returns the response for the requested page, it has no way of accessing any other windows that the browser might have. If you want to access other windows, you have to put client script in the page that does that.
--- It's amazing to see how much work some people will go through just to avoid a little bit of work.