You aren't calling the function!
 Code:
If InGroup('this group')
  DelPrinters() ; call the function
EndIf

Function DelPrinters()  ; define the function
  ; code goes here...
EndFunction
You DEFINE the function at the beginning or end of your main code, then you CALL the functions in your main code, as I've illustrated above.

A common mistake. \:\)

Glenn
_________________________
Actually I am a Rocket Scientist! \:D