Is there a way to add new items to enum in Objective-C?

Question

Possible Duplicate:
Possible to add another item to an existing enum type?

Say I have a class Car with the following enum defined:

typedef enum
{
    DrivingForward,
    DrivingBackward
} DrivingState;

Then, let's say I have a subclass of Car called Tesla and it happens to drive sideways too. Is there a way for Tesla to add new items to that original enum so that the final enum becomes like the following?

typedef enum
{
    DrivingForward,
    DrivingBackward,
    DrivingLeft,
    DrivingRight
} DrivingState;