Hi,
yes this can be done.
If there are checkboxes in an array you use the question type "array(numbers)"
where user can only select one of say 3 options
Do it exactly as you explained it.
Validate the question that the repondent cannot check two of theses options.
Something like:
(sum(Q1_SQ001_X001,Q1_SQ001_X002,Q1_SQ001_X003)<2) and (sum(Q1_SQ002_X001,Q1_SQ002_X002,Q1_SQ002_X003)<2) and (sum(Q1_SQ003_X001,Q1_SQ003_X002,Q1_SQ003_X003)<2) ...
Subquestions of x-axis coded as "X001", "X002", ...
Joffm