database issues after capturing

Our system has 10 Avid MC 3.5.1 systems networked to a Unity. We have one virtual drive set up for the users to capture to and one drive set up for project files. For the longest time now we have been finding large amounts of media files to be offline. Each machine has a file on the dedicated media drive that it captures to, ex avid #1 puts its media files in AVID1.1, and avid #2 in AVID2.1 all the way to ten. We found that all the media is still there and to get the media back all we have to do is delete the two database files and restart whichever avid is giving us the problem. Then we found what causes it. When a user opens a project and begins to capture instead of adding the newly captured media to the already existing database, it overwrites the database file with one that only links the media just captured in that project, leaving everything else that has been captured on that specific machine offline.

Does anyone know how to prevent this from happening?

Thanks in advance.

www.woodlandmedia1.com