As a new function, consider NP(User). This function would retrieve the Windows User ID currently running Jet and provide it as a potential filter to use in NL(Rows) and other functions. The advantage here is that retrieved results could be limited to only those relevant to the current user.
This function would be useful in situations where there are dozens, or even hundreds, of Viewers and the NAV administrators do not want to go thru and limit each one manually in NAV. I have done this for clients manually by using an Excel macro but it is not an elegant solution. NP(User) would be.