Multiple textbox question with NA option - by: kko

Hi, I need to add a question to LimeSurvey that allows users to enter up to 5 responses.

Question example: please list some of the music bands that you enjoy.

So, I decided to use "Multiple Short Text" question type and it works great. I've added 5 options with the same label "Enter text"

But in my example I want to add a checkbox "NA" at the bottom if they do not want to type-in any answers.

I have a requirement to have at least one of the fields populated OR NA checkbox checked.
Example:
__________
__________
__________
__________
__________
[_] NA

I know that I can set Mandatory "No" but this is a specific requirement that I need to follow.

Thanks a lot!