Data sharing between client and server two ways
The out-of-the-box solution for this in SQL Server is Peer-to-Peer Transactional Replication. This requires Enterprise edition at all nodes.

If your application truly needs this architecture, I would strongly recommend using the built-in tools rather than trying to patch something together using another technology. Peer-to-Peer replication was designed for this exact scenario.

Having said that, I would recommend that you make sure this architecture is actually necessary, as opposed to having one centralized database. I'm not saying this is the case in your scenario, but sometimes the people in suits can try to dictate a solution like you're asking for, without fully understanding the technical complexity. Setting up and managing this type of replication can be challenging.