How can I fix this HTML code?

I want to group these under the same name so the customer can only select one option, but when I give them the same group name the price is the price for option 1 even when adding button 3 to the cart. If I don't group them with the same group name then it works fine. Here is the code:

<form action="http://ww12.aitsafe.com/cf/addmu%E2%80%A6

<input type="hidden" name="return" value="www.malsforms.com/multiple-radio-…

<input type="hidden" name="userid" value="userid">

CUSTOMIZE YOUR PC<br>

<input type="radio" name="product1" value="2.5GHZ">

<input type="hidden" name="qty1" value="1">

<input type="hidden" name="price1" value="0.0">2.5GHZ (INCLUDED)<br>

<input type="radio" name="product2" value="3.0GHZ">

<input type="hidden" name="qty2" value="1">

<input type="hidden" name="price2" value="50.00">3.0GHZ (ADD + $50.00)<br>

<input type="radio" name="product3" value="3.6GHZ">

<input type="hidden" name="qty3" value="1">

<input type="hidden" name="price3" value="90.00">3.6GHZ (ADD + $90.00)<br>

<input type="submit" value="Buy">

</form>