Syncing an ACCESS-DB in a multiuser environment


We use an ACCESS-Database in a multiuser environment.
As we don’t have a web-Interface to the DB, multiuser-access is only possible, when the DB is on a local path.
As all users are working with the same local path, we will get data collisions, if all the users try to sync the same database at the same time.
I think, only ONE (i.e. the MASTER) of them should sync the local path to owncloud.
The problem is, that the MASTER computer is not running all the time. If data is changed from a different user, the cloud is out of sync until the MASTER is up again.
Can we solve this?