Silverlight is implemented as a browser plugin and is added to a web page as described here:
Integrating Silverlight with a Web Page[
^]
If you have more than one Silverlight application then you can integrate them with your web pages the same way. The .xap file name and/or URI will be different but that's it.
Your text doesn't make sense - adding a user control to a Silverlight application has nothing to do with the web page the Silverlight application is hosted on so you can't expect another test page.