Need help with Javascript and radio button

Hello

I have a form, and there is a section where there are 8 rows.
each rows has 2 text boxes and 4 radio buttons, each radio button has a value from 1 to 4, and in a ROW user can only select 1 radio button.

Suppose the 4 columns for the Radio Buttons are A,B,C,D

Now, at the end, i want to total all the A's, all the B's and so on. The problem is that each set of Radio Button has 1 name like SET1 is for Row 1 , SET2 is for ROW 2

The issue is that, i want to make a loop from 1 to 8
and then the script will check if the First Radio Button of SET1 is selected, then it will add 1 to A
OR
if the Third Radio Button of SET1 is selected, then it will add 1 to C

please guide me how i can do this ?
Also, how i can call the specific radio button like if I want to get the CHECKED status of 2nd Radio Button in 4th ROW, my current code is this :

var status = getField('SET4')[1].checked

but its not working !!!

Please guide