Hello,
I think this is the example you are looking for :
<ListBox Name="listbox" DisplayMemberPath="Test">
<ListBox.ItemsSource>
<CompositeCollection>
<CollectionContainer Collection="{Binding Source={StaticResource myDataSource2}, Path=One}"/>
<CollectionContainer Collection="{Binding Source={StaticResource myDataSource}, Path=Two}"/>
<CollectionContainer Collection="{Binding Source={StaticResource myDataSource}, Path=Three}"/>
</CompositeCollection>
</ListBox.ItemsSource>
</ListBox>
Hope this help you !