Outlook Archive unable to access

The company I work for has gone crazy for outlook archiving. I was asked to create an archive for our Accounting department and put it on one of our network drives, which I did. They want everyone in the accounting department (about 5 or 6 people) to be able to access it at the same time. Is this possible? I setup the archive file but when I try to give other user's access to it and someone's got it open I just get an error saying that I cannot access it because it is in use. Are there any settings or options I can change to share this file?

Any suggestions would be greatly appreciated.