If you are a long-time reader, you may recognize this AutoCAD tip by Robert Zipprich, as it was published back in 2003. Apparently it was never archived, so here it is once more. ZXP is a routine that lets you select the zoom XP scale from a dialog box and apply it to a viewport. You might be thinking that this ability is already part of AutoCAD, but Robert's routine works in older versions of the software, and also includes multiple scale units sorted by type, including Architectural, Engineering, Decimal, and Metric.
Start by copying both the LISP and DCL files into a directory that is part of your support file search path, then load the LISP file and run the command ZXP. If you are not currently in a viewport, the routine will prompt you to select one (and even switch to a layout if you are in MS). A dialog appears where you can select the correct zoom scale and press OK, or just double-click on the right choice. The displayed scales are coded into the LISP file, so it's easy to update the list — which in turn updates the choices for a group of users.