Just my two cents. Have you tried Jim's extended widgets? They certainly allow you add more questions on a slide and the choice of answers can be captured in a variable. I am not sure about sending that to LMS. You can probably post a comment on his post and he might answer you on that.
http://captivatedev.com/2012/09/16/adobe-captivate-6-x-free-widget-radio-buttons-enhanced/
Edit: They are NOT compatible with HTML5 outputs though.
Sreekanth