Can Objects has multiple classes?

[Ryan McDougall <NQG24419 nifty com>]

Hello,
	I want to set a per instance property that causes that object to look
up a vtable with slightly different semantics. The semantics of one
instance should not interfere with another. This requires two different
classes. The idea is to jump directly to the correct function without
incurring the cost of constantly (typeA)? fun1() : fun2(); by setting
the class pointer at initialization.

I wish to avoid sub-classing the the semantics since the API is exactly
the same, and it would cause an undue amount useless code. 

Is this possible with a minimum of hackishness?

ps. If you'd like an example, consider a reverse iterator which is
identical to forward iterator except next/prev functions are reversed.

Cheers,
Ryan