said by The WeaseL 
:Do you have a file server already in place? You could map a network drive and have a simple batch file do a copy from the local machine to the mapped drive every night at X:XX time.
Or just relocate the .pst files to the file server and change where Outlook looks for these files. Then back them up every night from that single location. Much easier then trying to ensure 50 machines are on and what not to pull data from.
That would be my recommendation.
There is a file server in place, but it doesn't have much space. That is why backups are only kept for two weeks before it is rewritten.
