ItemsControl.ItemTemplate bound to different Collection than ItemsControl

I have a bound treeview with an ItemsControl that dynamically creates the treeview items at runtime. However, to do this I have the ItemsControl ItemsSource bound to a different collection than the treeview is bound to. This works, but the issue comes with binding the textboxes in the ItemsContol, what should be displayed is actually a member of the SubOrganLocations but I can't seem to get the binding to work correctly. No matter what I do WPF is looking to bind to a property of the ItemsControl ItemsSource ProjectOrganLocation.LesionTypes instead of SubOrganLocations. Below is a snippet of the tree's XAML

<TreeView ItemsSource="{Binding GlobalOrganTree}">
<TreeView.ItemTemplate>
    <HierarchicalDataTemplate ItemsSource="{Binding SubOrganLocations}">
        <StackPanel Orientation="Horizontal">     
        <ItemsControl x:Name="ItemsControlGrid" ItemsSource="{Binding Path=ProjectOrganLocation.LesionTypes, Source={StaticResource Locator}}" >
            <ItemsControl.ItemsPanel>
     开发者_开发知识库           <ItemsPanelTemplate>
                     <StackPanel Orientation="Horizontal" />
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <TextBox Text="{Binding SubOrganLocations, Path=OrganLocation.Labels}"
                         Width="75" 
                         TextAlignment="Center"/>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
        </StackPanel>
   </HierarchicalDataTemplate>
</TreeView.ItemTemplate>

How can I get the textboxes bound to a SubOrganLocations property instead of a ProjectOrganLocation.LesionTypes property?

A RelativeSource is common when you need to bind to a DataContext that is higher in the tree:

<TextBox Text="{Binding Path=DataContext.Labels, RelativeSource={RelativeSource AncestorType={x:Type TreeViewItem}}}" />

This binds to a TreeViewItems's DataContext (an Organ) and gets the Labels from it.