Using timeline to make close captioning

I am trying to make closed captions for a product I am working on - that toggle. In order to do so, I have created separate text boxes that line up with audio on my time line and when the user clicks the CC button it will change the state of the text boxes to visible - and show another button that will make them change back to hidden. However, even though they are on the timeline and have specific timing for each, when I click the CC button and change the state of the text boxes, they are ALL showing up at the same time. What are my other options? The reason for making this is because the scrolling text box doesn't work very well on iPad, so I am forced to display the text in chunks to the audio instead. The only other way I could think of creating this is if you could add triggers/actions to cue points but that isn't possible.