Issue with radio boxes

I'm having an issue with the radio buttons in my form.
It's probably a noob issue, but I can't seem to find an answer.
 
I have a form for marking which has 4 criteria.
For each criteria, there are 5 choices for the marks, 1-5.
I have created sets of radio buttons for each criteria, and set it up so that feedback imports into a text field when the radio button is selected.
 
For criteria 1, I have 5 radio buttons, all called '1'. The value of each is '0'.
For criteria 2, I have 5 radio buttons, all called '2'. The value of each is '1'.
Its the same for criterias 3-5. Each has a different name and a different value to the other sets.
 
When I check a selection for criteria one, the box checks and the correct feedback is imported into the text box.
When I then select a radio box for criteria two, the check box for criteria one deselects, although the imported text remains.
Basically, only 1 check box out of all 20 can be selected at any one time, even though there are different names/values.
 
Help please!!!