Control structure with "not"

[Peter Bogdanoff]

Is it possible to convert this to a switch control structure, or otherwise refined somehow? The “not” is what I need, and the setting has to be always “true”:

on doThisThing tSender
	if tSender is not “Apple” then 
		set tSwitchApple to true
	end if

	if Sender is not “Peach” then 
		set tSwitchPeach to true
	end if

	if Sender is not “Grape” then 
		set tSwitchGrape to true
	end if
end doThisThing

Peter Bogdanoff
UCLA