Closed Captioning Timing Help

Hi, some of my slides have multiple sound files - either because the voice over was recorded/added in parts, or because some sound files are only meant to play if a button is clicked.  All sound files have closed captioning. 

My issue is that ALL the CC files display on the screen at once, at the start....even if the corresponding audio is not playing at that time. How can I control the CC timing/start time for slides with multiple sound files?

Any help would be greatly appreciated!