Users can now use Pervasync to synchronize multiple local PosrgreSQL and SQL server databases with a central PosrgreSQL or SQL Server database. Synchronization could be two-way, meaning writes can be done on both local and central databases. Data being synced can be defined by a sub-setting query. Change capture, conflict detection and resolution are built in to the core of the sync system.
Users can also sync Android SQLite databases with a central PosrgreSQL/SQL Server databases, which could be on premise or in the cloud (e.g. Amazon RDS databases).
Try Pervasync for free at http://www.pervasync.com