Okay, this may be extra work creating groups, but it may be the easiest way to set the primary printer when there are multiple printers installed.

Create a group specifically for a default printer group. Like DefPrinter_MRH-01_Q-MIS2 and put pcs in this group to get default/only printer of Q-MIS2. Create another group Printer_MRH-01_Q-MIS2 for users that have this additional printer. Use the SetDefaultPrinter in the script to set default printer if group name starts with DefPrinter.

tjcarst