Not Important - 2011-02-12

I would like to deploy compiere (custom version based on 3.5.2) into different locations (country) so there will be 2-3 databases that I will have to syncrhonize if I want to gather statistics globally for all instances (for example: which product had the most sell worldwide in january?). For performance reasons I need to create different Compiere instances and I need your help to understand what would be the best practices to make this syncrhonization ?