Is it possible for a child of a control that is a resource to reference (via a binding) a child control of a different resource?

[sam-wheat]

In the XAML below tb1 can be referenced by tb2 via a binding with no problems.
However tb4 generates a runtime error. How can I make tb4 bind to tb1 in the same way as tb2 ?

Runnable project attached.

<Window.Resources>
    <!--<TextBox x:Name="tb1" x:Key="tb1" Text="This is a resource."/> does not work -->
    <StackPanel x:Key="tbResources" >
        <!--<ContentPresenter Content="{StaticResource tb1}"/> does not work when referencing control outside this static resource -->
        <TextBox x:Name="tb1" Text="This is a resource."/>
        <TextBox x:Name="tb2" Text="{Binding Source={x:Reference tb1}, Path=Text}" /> <!--works-->
        <TextBox x:Name="tb3" Text="{Binding ElementName=tb1, Path=Text}" /> <!--Does not work-->
    </StackPanel>

    <StackPanel x:Key="tbResources2">
        <!--Runtime error here-->
        <TextBox x:Name="tb4" Text="{Binding Source={x:Reference tb1}, Path=Text}" />
    </StackPanel>
</Window.Resources>

ResourceTest.zip

[lindexi]

@sam-wheat We can use the resources many times. Which means that some object named tb1. And the tb4 hard to know which object to bind to.

[sam-wheat]

@lindexi Isn't tb1 a static resource? If so there should only be one instance. It seems to be working for tb2. In any case, is it possible to do what I ask?