Multiple instances of MultiSelectBehaviour

[Minh]

My currently program allows multiple instances of Views and using the code from the link below the SelectedItems property doesn't update for any instances created after the first. The first will always be update and trigger. 

    <telerik:RadGridView  ItemsSource="{Binding Items, Mode=TwoWay}"
                                        SelectedItem="{Binding SelectedTransaction, Mode=TwoWay}" " 
                                        IsEnabled="{Binding IsNotBusy, Mode=OneWay}"                                    
                                        SelectionMode="Extended"
                                        Framework:MultiSelectBehavior.SelectedItems="{Binding SelectedTransactions, Mode=TwoWay}">


https://github.com/telerik/xaml-sdk/blob/master/GridView/BindingSelectedItemsFromViewModel/MySelectedItemsBindingBehavior.cs

I was wondering if anyone can help me with this, my goal is to have each view's SelectedItems populate no matter how many instances are created.