Is it possible to synchronize two ms access db?
You can use the import data tools that are part of access to import data from one database into the other. It is under the "External Data" tab. This should work as long as you have network access to both databases.

Some more info : http://office.microsoft.com/en-us/access-help/import-or-link-to-data-in-another-access-database-HA001227658.aspx

Before doing this, have a little think about your table design - do you need to have a flag to indicate which store the data came from? If the data is normalized, you may have have issues importing data that may be resolved by the order that the data is imported in.

Also, remember to regularly backup these database files before trying to import. This way if you break something you can go back and start again. Also store them on physically different disks just in case....