MainObject
    List<NestedObject>
       NestedObject
           List<ChildObject>
               ChildObject
               ChildObject
               ChildObject
           List<ChildObject>
               ChildObject
               ChildObject
    List<NestedObject>
       NestedObject
           List<ChildObject>
               ChildObject
           List<ChildObject>
               ChildObject
               ChildObject
       NestedObject
           List<ChildObject>
               ChildObject
               ChildObject

private IEnumerable<T> Iterate<T>(Type type)
{
    foreach(var p in typeof(type).GetProperties()) {
        IEnumerable<T> collection = p as IEnumerable<T>;
        if (collection != null){
            return collection
                .OfType<T>()
                .Concat<T>(property.SelectMany(p => Iterate<T>(p)));
        }
    }
}