Load XML URL from external file

xmlData = new XML();
xmlData.ignoreWhite = true;
xmlData.onLoad = loadXML;
xmlData.load(http://www.someothersite.com/rss.xml);

in this code- is there anyway i can load the URL from an external file?
Here: xmlData.load(myURL);can “myURL” be loaded from an external source… may be from another XML file which i can keep locally and change the URL when needed.