Here is a thought experiment similar to the one given by Passionflower with an added twist, that gives a perhaps non-intuitive result. A and B are initially adjacent and at rest wrt each other. B accelerates to 0.99c in a couple of minutes (ignore the practical difficulties) and then cruises for aproximately one year according to A, who up to now has not undergone any acceleration. Now instead of B coming to rest in A's frame, A does a rapid burst of acceleration (lasting a few minutes) in B's direction and comes to rest in B's frame, but they are still far apart.
The slightly surpising result, if I have worked it out correctly (and I might not of, because I am a bit tired) is that A (who has a spent a year lazing around while B hurtles off at 0.99c relative to him) has aged less than B. It seems that the twin that ages the most, is the one that does the short final burst of acceleration to come to rest in the other twin's rest frame.
As I'm sure you know, a spacetime diagram shows exactly what is going on. Without giving it too much thought I would imagine that you can, by using appropriate figures, set up a similar scenario where they age by the same amount.
As usual its just about path lengths. Spacetime diagrams let you visualize what is going on and calculation confirms it.