Getting root node id based on a given child id in XML

[thegame11]

Here is my XML structure:\[code\]<DirectoryNode Id="297fe1ac-ff9b-4c40-ada4-86dc713a9537" Title="Root"> <DirectoryNode Id="80e01248-1170-4393-a327-b97409d51159" Title="A"> <DirectoryNode Id="e6db6d3f-be30-4cdf-b79e-864cc9b52c5f" Title="A1"> <DirectoryNode Id="4368d898-6fb0-4e2f-ba56-edbaf4bd0077" Title="A11" /> </DirectoryNode> <DirectoryNode Id="11c5336b-462e-45dc-b4d3-92032ebc3ae3" Title="A2" /> </DirectoryNode> <DirectoryNode Id="b983fd39-fc2e-43e0-80e6-3808fb47f995" Title="B"> <DirectoryNode Id="433851d6-9935-4adb-9acb-7055c26e85cb" Title="B1"> <DirectoryNode Id="f2602aed-6d97-4e46-9e8a-fb181b28f0c8" Title="B11" /> </DirectoryNode> </DirectoryNode> <DirectoryNode Id="9144d8cf-93c0-4de6-9109-448d396a9e17" Title="C" /> <DirectoryNode Id="182491af-452e-40bc-b51e-59f078db3ad3" Title="D" /></DirectoryNode>\[/code\]What I'm trying to do is get the root node (not the main root node) id given a directory node id. Here's some examples:[*]Given A11's Id, I want A's Id[*]Given A2's Id, I want A's Id[*]Given A's Id, I want A's Id[*]Given B1's Id, I want B's IdI'm horrible when it comes to parsing xml and pulling out values - does anyone know a quick way to do this?