I assume you are using SQL Server at the main database but what databases are you using at the n-hubs? If it is SQL Compact then the Sync Services for ADO.NET component of the Sync Framework should allow you to easily synchronize a primary key table to each of the hubs.
Unfortuantely SQL Express is not officially supported as a client (or in your case as an N-Hub) even though we do have a sample on how to accomplish this.
Certaily it is always possible to use the Sync Framework to synchronize anything to anything, however, if Sync Services for ADO.NET allows you to accomplish what you are looking to do it might be simpler from an implementation standpoint to use it.
Liam