All you need to do is to provide the second group of radio buttons with a different name to that used for the first group.
The name field determines which group that a particular button belongs to.
where the first argument is either a collection of radio buttons, or the name of the button group.
The second argument is a reference to the containing form, though its only necessary if a string is used for the first argument.
That completes the coding of the radio buttons themselves.
Given a reference, form, you could check the group with either of the following expressions.
The setup and validation of radio buttons appears to be the form field that gives many webmasters the most difficulty in setting up.
The first example shows how to validate a checkbox if nothing is checked.
This is similar to radiobutton example explained above.