Ok, I've figured this out. In case anyone else is struggling this is what I did. I had to add the addtional column for my survey answers to my secondary data source. Maybe this is infopath 101 but I'm a newbie. Once I added the column I also needed to give the fields a default value. Without the default value the radio buttons were read only.
Since there are over 100 table rows I also wanted to populate 5 fields on the form with the values of the corresponding survey answers. For instance a list of all values with an answer of 1, another with all 2s, etc.. I used this default value formula to do that: eval(eval(Skills_List[@SkillLevel = "1"], 'concat(@Skill_Name, ";")'), "..") This returns all Skill_Names from Skills_LIst with a SkillLevel of 1, separated by semicolons.
Hope this helps someone.
Happy New Year! Have a great 2008.
Brad