Traverse upwards in JSON when mapping using RestKit 0.20 - ios

Question

I have the following JSON structure:
{
"category": "MyCategory"
"objects": [
{ "id": 1, "name": "A" },
{ "id": 2, "name": "B" },
{ "id": 3, "name": "C" }
]
}
I'm mapping each object to a separate Core Data entity like this:
RKEntityMapping *mapping = [RKEntityMapping mappingForEntityForName:#"Object" inManagedObjectStore:manager.managedObjectStore];
mapping.identificationAttributes = #[ #"id" ];
[mapping addAttributeMappingsFromDictionary:#{ #"name": #"name" }];
How do I configure the mapping to store their shared category on each object?
The thing I would like is to be able to traverse upwards in the JSON like this:
[mapping addAttributeMappingsFromDictionary:#{ #"name": #"name", #"PARENT.category": #"category" }];

Answer 1

As of now (RestKit 0.20.1), there is no way to do this by using the mapping engine.
FUTURE
There is a new metadata feature under development making it possible to access the parent object:
[mapping addAttributeMappingsFromDictionary:#{ #"name": #"name", #"#metadata.parentObject.category": #"category" }];
PRESENT
I'm modifying my deserialized response using willMapDeserializedResponseBlock. I've added a category on RKObjectManager to make it easy to modify the response:
https://gist.github.com/gunnarblom/5677324