Are there any AS3 classes to help arrange objects into layers, like in the designer, such that the objects all have the same parent?

Obviously, I can use container clips to simulate layers, but I specifically want this kind of functionality for objects that have the same parent.

My understanding is that the design-time notion of layers does not exist at run-time, and objects just have a depth index.

I'm creating a class to simulate layering functionality with a single parent, but if one already exists, I'd like to check it out.

On a side note... how do design-time layer masks manifest themselves at runtime in AS3? I thought maybe all objects on the masked layer share the same mask object, but the "mask" property appears to be null for all objects on the masked layer, even though they share the same parent timeline as the unmasked objects (i.e. unmasked layer object parent == masked layer object parent; therefore, no masked subcontainers appear to be in use).