  Continuing the study in hep-th/0004092 and hep-th/0004092, we investigate a
non-trivial string dynamical process related to orientifold planes, i.e., the
splitting of physical NS-branes and D(p+2)-branes on orientifold Op-planes.
Creation or annihilation of physical Dp-branes usually accompanies the
splitting process. In the particular case p=4, we use Seiberg-Witten curves as
an independent method to check the results.
