Automapper Mapping of simple object to more complex nested type

Question

I am in the process of a refactor and utilizing AutoMapper (6.2.1) to help us in formatting of API returns that conform to a specific contract. The DTO objects we are using internally are meant to simplify our understanding of the data before returning the data in the more complex type.

The Issue: I have a DTO with a List<T> where I need one of the properties of <T> to be mapped to the collection in the more complex type. This is actually pretty straight forward but the problem is, what if the collection I am trying to map to in the more complex type is in fact inside another "higher" collection. Essentially I am in a little bit of a collection inside a collection problem.

Ex: DTO

public class ItemDTO
{
   List<ItemDescriptionDTO> ItemDescriptions { get; set; }
}

public class ItemDescriptionDTO
{
    public string Description { get; set; }
}

More Complex object I need to map to and do not have control over

public class ComplexThing // This is the object I need (It's ugly, I hate it too)
{
    public ComplexItemDescriptions { get; set; }
}

public class ComplexItemDescriptions 
{
    public List<ComplexItemDescription> ComplexItemDescription { get; set; }
}

public class ComplexItemDescription
{
    public UnparsedItemDescriptions UnparsedItemDescriptions { get; set; }
}

public class UnparsedItemDescriptions
{
    public List<UnparsedItemDescription> UnparsedItemDescription { get; set; }
}

public class UnparsedItemDescription
{
    public string UnparsedItemDescription { get; set; }
}

In essence I need to take the Description in my simple ItemDescriptionDTOand map that through this awful chain of nested objects to set the UnparsedItemDescription

I am able to properly map from UnparsedItemDescription all the way to the ComplexItemDescription but going higher than that to the Complex thing is giving me some trouble.

This is the mapping I have so far:

config.CreateMap<ItemDescriptionDTO, UnparsedItemDescription>()
    .ForMember(dest => dest.UnparsedItemDescription, map => map.MapFrom(src => src.Description));

config.CreateMap<ItemDTO, UnparsedItemDescriptions>()
    .ForMember(dest => dest.UnparsedItemDescription, map => map.MapFrom(src => src.ItemDescritpions));

config.CreateMap<ItemDTO, ComplexItemDescription>()
    .ForPath(dest => dest.UnparsedItemDescriptions.UnparsedItemDescription, map => map.MapFrom(src => src.ItemDescriptions));

// This is where we start failing (I think I am just not understanding something fundamental to how Automapper does things or I am up against some silly edge case
config.CreateMap<ItemDTO, ComplexItemDescriptions>()
    .ForMember(dest => dest.ComplexItemDescription, map => map.MapFrom(src => src.ItemDescriptions));

I need the ComplexThing because there are other properties in that class that are returned so I can't just get away with returning say a ComplexItemDescription

I would appreciate an assistance you could give. I admittedly have a base understanding on how Automapper works (which I am in the process of trying to get better at) but this is really throwing me at the moment.