If using 10.1 FR1 or below you need to look into SQL push/merge replication. Its covered in the guides. You would setup two databases, one in each location, two EMPS servers, one in each location, and then setup replication between the databases.
If using 10.1 FR2 you can use the new GeoSync feature instead of SQL replication. Its also covered in the guides. If after reading those you have questions let me know.
Thanks for the reply.
Where are these guides please?
They are in the guides folder when you unzip the suite installer.