Simple grouping in ListBox

<Grid>
<Grid.Resources>
<XmlDataProvider x:Key="Company" XPath="/Company">
<x:XData>
<Company xmlns="">
<Person Name="Jack" Role="CEO"/>
<Person Name="Tim" Role="PL" />
<Person Name="Jil" Role="PL" />
<Person Name="Jimmy" Role="PM" />
<Person Name="Joy" Role="PM" />
<Person Name="Jim" Role="PL" />
<Person Name="Jack" Role="PM" />
</Company>
</x:XData>
</XmlDataProvider>

<DataTemplate x:Key="categoryTemplate">
<TextBlock Text="{Binding Path=Name}" FontWeight="Bold" Background="ForestGreen" Margin="0,5,0,0"/>
</DataTemplate>
<DataTemplate x:Key="template">
<TextBlock Text="{Binding XPath=@Name}"/>
</DataTemplate>

<CollectionViewSource x:Key="cvs" Source="{Binding Source={StaticResource Company},XPath=Person}">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="@Role"/>
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
</Grid.Resources>


<ListBox Name="lst"
ItemTemplate="{StaticResource template}"
ItemsSource="{Binding Source={StaticResource cvs}}">
<ListBox.GroupStyle>
<GroupStyle HeaderTemplate="{StaticResource categoryTemplate}" />
</ListBox.GroupStyle>
</ListBox>
</Grid>

If you want to sort items in these groups please use SortDescriptions along with GroupDescriptions.For more details visit
http://www.beacosta.com/2006/01/how-do-i-sort-groups-of-data-items.html