Group permissions

Thank you igoth60 for the excellant link. I am fortunate that the vast majority of our users are within a group so that is good, unfortunately, I don't know of a way to know what files the group is assigned. Example, we have two groups, Engspcl (50 users, 32 no longer here) and Engspcls (43 users, 27 no longer here) Both have users in common (yes, lots of clean up to do). I know the users have drives mapped to several shared directories on a file server. Since we have so many files, how can I tell without looking at every single file on the server which ones each group has access to? Also with disrupting business for the remaining users? I have inherited a network started in '99 gone through 4 network admins. I need to get this cleaned up and under control to be able to manage. I have worked in the IBM world where you have a user profile and you assign them to a group then you assign the files to the group. MS world seems opposite, you have user profile, member of a group, group assigned to the file. So is there some sort of miracle tool that can scan all files on a server and list the users or groups assigned to it with permission type? Some sort of 'where used' on a user profile? Please excuse my ignorance and thank you for your help.