S2PX requires a solution which supports the same capabilities as Server hashed files:
A single hashed files can act as both a source and target within the same job.
A single hashed file can be referenced by multiple source and target stages within the same job.
A hashed file stage can use keys values to enable the upsert of its data.
Hashed files provide database record locking so that a single job or multiple jobs can read from and write to the same hashed file concurrently.
Commonly considered Hashed File alternatives such as Sequential Files, Data Sets and File Sets are unable to support the functionality described above.