Check box or radio buttons

Hello,

I created a spreadsheet with the easy-to-use check box function. I see that what this really represents is a TRUE/FALSE value in each cell, which makes sense. Is there any way, with check boxes, to allow only one answer to a question? I know that's technically what a radio button is supposed to do, but the check box feature is much neater.

In the attached example, four businesses are listed and the end-user can select if the business is a client in our region, a client outside of our region, or not a client at all. The ideal would be if only one check box per client can be selected.

Thanks for pointing me in the right direction!