Assigning audios to variables

Hello,

I am developing a Storyline template for developers that would allow them to simply enter their content in the Variable pane and they will be good to go. Basically, the template has 3 nodes that will show the content. I also have layers in my project that serve as permutations and combinations of 3 nodes. For instance, if a user clicks node 1, he will land on the layer where node 1 is expanded. On that layer, now if a user clicks node 2, then both node 1 and node 2 should show up. They also have an option to collapse a node. Now, on the screen where node 1 and node 2 were expanded, a user collapsed node 2, then they should land on a layer where only node 1 is expanded but node 2 has a check mark next to it, denoting that it has been visited. So I have 27 layers for 3 different nodes, implying that each node can have 3 combinations. I am using three variables for each of three nodes, so that when the developer populate the content in the Variables pane, the same content reflects across all 27 layers in those nodes, and they don't have to do that across 27 layers.

Now, I want to implement a functionality where a developer can assign different audio to each of the three variables and the audio should be played everytime the respective node is clicked. This could have been an easy ask if there were no layers, but since I have 27 layers (and they are dynamic) and I want everytime a user clicks a particular node, the respective audio should be played, this is sounding a tough nut to crack. Basically, I want whosoever uses this template, should just be assigning audio to 3 variables and that should be reflected across all layers instead of adding trigger to play audio on each layer. I am attaching the .story file and each three audio files. Any help is appreciated. Thanks!