Sharing parent value when mapping a list of objects

gistfile1.m

// {
//   "category": "MyCategory"
//   "items": [
//     { "id": 1, "name": "A" },
//     { "id": 2, "name": "B" },
//     { "id": 3, "name": "C" }
//   ]
// }

// Current mapping, but missing "category" object that should be mapped to each "Item"

RKEntityMapping *mapping = [RKEntityMapping mappingForEntityForName:@"Item" inManagedObjectStore:manager.managedObjectStore];
mapping.identificationAttributes = @[ @"id" ];
[mapping addAttributeMappingsFromDictionary:@{ @"name": @"name" }];
// TODO: Also add "category" to this mapping