XML解析 - 仅从具有特定ID的父节点获取节点

I am building a steam-clone game manager in Java and I am having problems with one final part of the project. On the left hand side of the GUI I have automatically populated "playlists" of games that are parsed from a library XML file, and I would like to retrieve the games from only that playlist when it is clicked on through a ListSelectionListener. I am currently able to populate ALL games stored in the library by using getElementsByTagName("Game"), but I need them to be specific to the playlist which is also assigned a unique id with an attributeID set to true for "Id". I am building a steam-clone game manager in Jav