Correct, the synchronization is one way, you could synch from Development to Staging, but once you have synchronized from Development to Staging, you should not synch from Staging to Development
Regarding synchronization scenarios I would suggest you to review this article:
You scenario could be achieved is Staging Americas and Staging Asia - Pac are using one database and are in NLB and Production Americas and Production Asia -Pac are using one database and are in NLB.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Sitefinity CMS Ideas&Feedback Portal
and vote to affect the priority of the items