如何通过包含它的对象的接口公开私有内部对象的依赖属性？

We have a custom panel class that animates its children via an internal DoubleAnimation object. However, we want to expose the animation's Duration dependency property as a public property of our panel so the user can change it in their XAML when using our panel. But we don't want to expose any other part of the animation object, just the duration.We have a custom panel class that animates its