位于另一个网格(zIndex= 1)后面的网格(zIndex=0)的WPF Clickevent

我尝试创建一些网格。在每个网格上，我都有一个鼠标事件监听器，当我将鼠标移动到这个网格上时，它会触发一个事件。现在我创建一个大网格，zIndex = 1, Rowspan = 3。这个网格位于前面(因为zIndex = 1)。现在我有问题来触发位于zIndex = 1的大网格后面的网格事件。如何触发位于大网格后面的网格事件?

简单代码示例:

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
    </Grid.RowDefinitions>
    <Grid Grid.Row="0" Background="AliceBlue"/>
    <Grid Grid.Row="1" Grid.RowSpan="3" Panel.ZIndex="1" Background="Aqua" Opacity="0.2" PreviewMouseMove="Grid_PreviewMouseMove_1"/>
    <Grid Grid.Row="2" PreviewMouseMove="Grid_PreviewMouseMove" Background="AntiqueWhite"/>
    <Grid Grid.Row="3" PreviewMouseMove="Grid_PreviewMouseMove" Background="Beige"/>
    <Grid Grid.Row="4" PreviewMouseMove="Grid_PreviewMouseMove" Background="Bisque"/>
    <Grid Grid.Row="5" PreviewMouseMove="Grid_PreviewMouseMove" Background="BlanchedAlmond"/>
</Grid>