Well, what I think is that to be "revived" there has to be no "essence" of Orochimaru in the world. It could be said that he splits his own life when putting a curse seal, though when doing so the life force because a force for the one with the curse seal. The reason why a curse seal may hurt when being close to Oro is because it may resonate with him.
If there is no more "main" Orochimaru in the world, any life force that he kept on a curse mark can replace him, becoming Orochimaru itself. When he is revived though, there cannot be another one revived as there is already an Orochimaru resonating his essence through the rest of the curse marks.