Hi Martin,
I suspect that you'll have to derive from the DataGridViewComboBoxCell or
DataGridViewComboBoxColumn classes.
Here's an article that I haven't read myself, but it looks like it may be
useful to you:
"Build a Custom RadioButton Cell and Column for the DataGridView Control"
http://msdn2.microsoft.com/en-us/library/aa730882(vs.80).aspx

Signature
Dave Sexton
> Hi!
>
[quoted text clipped - 4 lines]
> Regards
> Martin