Java Programming

I have and XML file that looks like this:

<boxes>
    <box>
      <brown>
          <closed/>
      </brown>
    </box>
    <box>
      <green>
          <open/>
      </green>
      <brown>
          <closed/>
      </brown>
    </box>
</boxes>

I am trying to create objects that the above XML file can be parsed to with XStream. But how do I make a list of Box objects that can be both brown and green?