I may have a suggestion, but it will depend on how you use the xml file and who who takes care of it.
You could make a special
(special to you) tag that will mean something for you when you parse the xml.
For example:
<notes>
<note>
<to>Person1</to>
<myAddress></myAddress>
<heading>Reminder</heading>
<body>Don't forget to do stuff</body>
</note>
<note>
<to>Person2</to>
<myAddress></myAddress>
<heading>Assignment</heading>
<body>You need to do stuff!</body>
</note>
....
</notes>
<myAddressDef>
<name>Me</name>
<position>Boss</position> <!-- Because why not :) -->
....
</myAddressDef>
Every time you encounter myAddress
tag, you will know that it's „defined” under the myAddressDef
tag and get the content from there.