Xamarin forms access element outside a ControlTemplate - xaml

Question

I'm trying to find out a way to access a named element outside a ControlTemplate, or viceversa, access a named element inside a ControlTemplate from outside, from XAML (not code behind).
Let's suppose I have the following code:
<ResourceDictionary>
<ControlTemplate x:Key="MyControlTemplate">
<views:MyView x:Name="MyViewName">
<views:MyView.Triggers>
<DataTrigger TargetType="views:MyView" Binding="{Binding MyProperty}" Value="True">
<Setter TargetName="MyCollectionView" Property="IsEnabled" Value="False"></Setter>
</DataTrigger>
</views:MyView.Triggers>
</views:MyView>
</ControlTemplate>
<ControlTemplate x:Key="MyOtherControlTemplate">
<views:MyOtherView x:Name="MyViewName"></views:MyView>
</ControlTemplate>
</ResourceDictionary>
<CollectionView x:Name="MyCollectionView">
...
</CollectionView>
<TemplatedView
Grid.Row="1"
ControlTemplate="{StaticResource MyControlTemplate}"/>
<TemplatedView
Grid.Row="1"
ControlTemplate="{StaticResource MyOtherControlTemplate}"/>
This code is inside a ContentView. Which shows, depending on the selected item in the CollectionView, a view (MyView) or another view (MyOtherView). If MyProperty (which is a property inside the view MyView) is True, then I want the collectionView to be disabled. Since MyView is declared inside the ControlTemplate, I can't manage it to access to MyCollectionView
Where MyProperty is a boolean inside MyView ViewModel.
This code throws ArgumentNullException: Value cannot be null. Parameter name: targetObject.
Apparently, MyCollectionView is unknown inside the ControlTemplate
I have also tried to reference to MyView's name in a DataTrigger of MyCollectionView and it has no result.
Can anyone help me?