As far as I know, it has to be done programmically.  You can trap the print
statement and place code similar to that below in that particular document.  
Make sure you re-set the printer back to the user's default after printing.

Hint:  Get the exat printer name by recording key strokes to send to that
printer

Dim strCurrentPrinter as string

'Grab the user's existing printer default

strCurrentPrinter = ActivePrinter

'Reset to the printer of your choice

ActivePrinter = "[name of your printer and path" '(i.e., "\\network name\HP
LaserJet 9000 Series")

'If you want to allow the user to print only parts of the doc, show the
print dialog

   Dialogs(wdDialogFilePrint).Show

'Use the following code to set bins if you wish

   With ActiveDocument.PageSetup
       .FirstPageTray = wdPrinterAutomaticSheetFeed
       .OtherPagesTray = wdPrinterAutomaticSheetFeed
   End With

'Re-set back to the user's pre-selected printer

ActivePrinter = strCurrentPrinter

Hope this helps