Menu filtering using xpath

[Max]

Hi! Im using radmenu like this:

<Menu>
  <Item text="lvl1" Role="A">
    <Item text="lvl2" Role="A">
      <Item text="lvl3" Role="A" />
      <Item text="lvl3" Role="B" />
    </Item>
    <Item text="lvl2" Role="B" />
  </Item>
  <Item text="lvl1" Role="B">
  </Item>
</Menu>

<asp:XmlDataSource DataFile="LikeAbove" ID="xmlDataSource" XPath="//Item[@Role='A']" runat="server />
<telerik:RadMenu DataSourceID="xmlDataSource" runat="Server">
  <DataBindings>
    <telerik:RadMenuItemBinding Depth="0" TextField="Text" />
    <telerik:RadMenuItemBinding Depth="1" TextField="Text" />
  </DataBindings>
</telerik:RadMenu>

What Im trying to do is to get all menu items with the role "A", filtering on all levels. I works on a single level using this /Item[@Role='A']but when using this approach on a multi level //Item[@Role='A'] (two slash in the beginning) it "flats out", meaning all menu nodes are being visible on the first level AND also still remains unfiltered where they used to be in the tree.

[Max]

Or if someone has another approach how to make menu items hidden depending on their role, please share! Still I'd like to have an xml file as the datasource.