modified files on NAS do not update in finder

We have four mac pros running 10.7.5 with final cut studio. Our media is on a NAS that all four systems access. We have a problem when we rename files on one system and the changes do not show up on the other three systems. The only work around we have found is to restart the mac. We just tried an application found online called "Refresh Finder" that got very positive reviews but that doesn't seem to do anything (or it's being installed and used incorrectly). Does anybody have suggestions on how to solve this problem. It would be a big help.

Thanks,

Mike