Multi audio for mmd animation list

Questions
,
1

example of MMDAnimationHelper,
there supports only one audio file. but i want play List of audio files.

const soundFiles = ['audio1.mp3','audio2.mp3'];
const motions= ['motion1.vmd','motion2.vmd'];
const camMotions =  ['cam1.vmd','cam2.vmd'];
const mixer=helper.objects.get(mmd.mesh);
mixer.addEventListener( ‘finished’, a_variable = (e)=>{
  // here is Animation onfinished.
  // i don't know to put code here as just i need.
  mixer.removeEventListener(‘finished’, a_variable);
});

new THREE.AudioLoader().load(soundFiles[0], function (buffer) {
        const listener = new THREE.AudioListener();
        self.data.camera.add(listener);
        const audio = new THREE.Audio(listener).setBuffer(buffer);
      helper.add(audio, audioParams);
});