您可以将您拥有的内容包装在RibbonGroup中,在组的右侧创建一个垂直分隔符。

我所做的只是将第一个按钮包裹在RibbonGroup.
<ribbon:RibbonTab x:Name="HomeTab"
Header="Home">
<ribbon:RibbonGroup x:Name="Group1"
Header="Group1">
<ribbon:RibbonGroup>
<ribbon:RibbonButton x:Name="Button1"
LargeImageSource="Images\LargeIcon.png"
Label="Button1" Margin="-5" />
</ribbon:RibbonGroup>
<ribbon:RibbonButton x:Name="Button2"
SmallImageSource="Images\SmallIcon.png"
Label="Button2" />
<ribbon:RibbonButton x:Name="Button3"
SmallImageSource="Images\SmallIcon.png"
Label="Button3" />
<ribbon:RibbonButton x:Name="Button4"
SmallImageSource="Images\SmallIcon.png"
Label="Button4" />
</ribbon:RibbonGroup>
</ribbon:RibbonTab>