Two
Story Concept:
In Phantasy Star 2, the planet Palma (Palm) was destroyed. But in Phantasy Star 3 we learned that many colony ships had successfully escaped that destruction along with large groups of Palmans, we followed the journey of one of those ships. In PSO it appears that we follow the journey of another such colony ship.
It is fairly safe to assume, considering the history of Algo, that no passenger of any of those ships will completely escape the curse of never finding true peace, a curse that has been a part of their history for thousands of years.