This would work beautifully with the optionbutton from the forms toolbar -
any ideas how to make the group box smaller or the line around it invisible?!
(these little details...)

In testing out your idea, though, I realise that I should be linking my
activex optionbuttons to three different cells (so I get a FALSE/TRUE/FALSE
effect which updates in unison) - so actually you did solve my problem.
Thank you!