You'll have to pipe all your ratings into either a web service or JavaScript that determines and sets embedded variables for the attribute you want to ask about. Personally, I would opt for a web service script unless it is in a loop & merge block in which case you would have to use JavaScript.
@joemp - There are a few ways to achieve this without JavaScript. I demonstrated one of the ways in the attached .qsf (qualtrics save file a.k.a. a survey I built to demonstrate this). Save the .qsf and upload it as a new survey to understand what I did.
A couple of things - You only wanted to display a question for the respondent to provide feedback for only one of the categories they may have rated low. I would not recommend this and would either ask for feedback in all areas they rated low _or_ ask for feedback on how their performance could be improved
agnostic of their rating. Not only is this by far the easiest to program, you also avoid potentially loaded question wording.
In any event, please refer to the .qsf for further explanation. Note - most of the programming is done in the survey flow section.
Feel free to PM if you have any questions.