WPF Binding Two Checkboxes with IsChecked Property

I have a WPF UI, with the following elements:

• The checked checkbox is in a DataGridRow.


• The rest is in the DataGridRowDetails. (It contains a smaller DataGrid)

What I want to get done is to bind the two (shown by red arrows) checkboxes together, so that when one is checked, the other also gets checked, and vice-versa.

I have already taken a look at these questions:

1) WPF Binding with 2 Checkboxes

But when I try this, the click handlers stop working. (The checkboxes stop working altogether)

2) wpf bindings between two checkboxes

When I use triggers, one checkbox triggers the other, and it inturn triggers the other, and goes on.. UI gets stuck.

Sample of my code:

<DataGrid x:Name="DataGrid1">
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>


                    <CheckBox x:Name="SelectionCheckBox1" PreviewMouseLeftButtonDown="SelectionCheckBox1_PreviewMouseLeftButtonDown"
                              Loaded="SelectionCheckBox1_Loaded"
                              IsChecked="{Binding ElementName=HeaderCheckBox1, Path=IsChecked, Mode=TwoWay}">
                    </CheckBox>


                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
    <DataGrid.RowDetailsTemplate>
        <DataTemplate>
            <DockPanel LastChildFill="True">
            <DataGrid>
                <DataGrid.Columns>
                    <DataGridTemplateColumn>
                        <DataGridTemplateColumn.HeaderTemplate>
                             <DataTemplate>


                                 <CheckBox x:Name="HeaderCheckBox1" PreviewMouseLeftButtonDown="HeaderCheckBox_PreviewMouseLeftButtonDown"
                                           IsChecked="{Binding ElementName=SelectionCheckBox1, Path=IsChecked, Mode=TwoWay}">
                                 </CheckBox>


                             </DataTemplate>
                    </DataGridTemplateColumn.HeaderTemplate>
               </DataGrid.Columns>
           </DataGrid>
           </DockPanel>
       </DataTemplate>
    </DataGrid.RowDetailsTemplate>
</DataGrid>

Concern : Because the second Checkbox appears only after the row is selected ( which means the other checkbox is selected), I am unable to find the second checkbox through VisualTreeHelpers also.

Some idea even leading to a possible solution will be much appreciated.