Getting the checkbox item that was checked in MPF with MVVM

I'm currently trying to implement ctrl & shift selection capabilities on a long list of checkbox items. Right now, you can highlight/select items by clicking on the names in the list, and you can select groups by using ctrl or shift. I'd like to allow group checkbox toggling by checking/unchecking all selected items if an item in the selection has been checked/unchecked.

This means trying to retrieve the item that was checked/unchecked and comparing its IsSelected property.

This post is the closest thing I could find to the what I'm looking for.

This is the xaml I have right now:

<ListView Name="LeftListView"
          Grid.Row="4" Grid.Column="1"
          ItemsSource="{Binding CvsLeftListView}">

    <ListView.ItemContainerStyle>
        <Style TargetType="{x:Type ListViewItem}">
            <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
        </Style>
    </ListView.ItemContainerStyle>

    <ListView.ItemsPanel>
        <ItemsPanelTemplate>
            <VirtualizingStackPanel Orientation="Vertical"/>
        </ItemsPanelTemplate>
    </ListView.ItemsPanel>

    <ListView.ItemTemplate>
        <DataTemplate>
            <VirtualizingStackPanel Orientation="Horizontal">
                <CheckBox Name="LeftListCheckBox"
                          IsChecked="{Binding Path=IsChecked, Mode=TwoWay}"
                          Command="{Binding Path=DataContext.CheckBoxChanged, RelativeSource={RelativeSource AncestorType=ListView}}"
                          Checked="LeftListCheckBox_Checked" Unchecked="LeftListCheckBox_Unchecked"/>
                <TextBlock Name="LeftListName"
                           Text="{Binding Name}"
                           Margin="2,0,0,0"/>
            </VirtualizingStackPanel>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>