Hi,
You need the three radio buttons in one cell. In the hierarchy view drag buttons 2 and 3 back into the radio 1 exclusion group on the second column. To mimic a table, turn the top and bottom lines off on the cell and turn on the top and bottom lines on the three radio buttons. Get the radio buttons the same size (it helps to have snap to grid off), same reserve and aligned. Then delete the two bottom rows and it should look like a table again.
Good luck,
N.
ps if users are going to fill this in by hand as well, you could follow Jono's example and have the radio buttons with a sunken square and square mark. The square is more intuiative on page and even on screen the square stands out more against the user's choice. I appreciate that the use of sunken squares works against the best practice of circles for exclusion groups, but with your form, I suspect that clarity is important as the choices may be "health"; "have you made a will?"; "beeeeeeeeep!" ;-)