Single Video with different audio topics describing video

We have a small medical clinic that has added video to our daily treatments.  The video will be utilized by graduate students and licensed professionals to learn techniques. A single video contains multiple topics of discussion eg - scar management.  Another topic of the same video might be modalities used. The idea is that a student can click on one topic and see/watch the video with the audio voice over of the topic -Scar management. For example, a patient has amputated fingers that have been replanted/reattached and the scars will require management to allow the tendons to begin gliding again. Scar Management might be menu item One. The next menu item might be modalities used during rehab. Click on menu item Two and the same video plays but with the audio addressing menu item two - Modalities. Menu item Three might be Interventions developed during rehab with the entire discussion focused on interventions. 

We would prefer to use the single video file - no duplicates - but separate audio for each menu item. Is this possible and if so, where can we get started? Eventually we will hire some folks with the skills to do what I described but for now, we need direction to get started so we can experiment with different presentations. I appreciate your help.