Easy.
For the secure database, specify the mdw on the command line of a shortcut
(lookup command line parameters in Access Help)
For all other usage (such as double-clicking an mdb), do not specify an mdw
and it will default to the default (system.mdw in the default folder).
DO NOT alter the mdw from the default system.mdw in the Workgroup
Administrator. You bypass that default by specifying another one (payroll.mdw)
in a specific (desktop) shortcut for that app.
Chris