set duration playing with exoplayer

I have a service player, which is working well. I have list audio sounds, which I want to play sequentially during the different minute times.

My code :

 val sourceList = mutableListOf<ExtractorMediaSource>()
    listSounds.forEach {
       val uri = RawResourceDataSource.buildRawResourceUri(it)
       val source = ExtractorMediaSource(uri, dataSourceFactory, extractorsFactory, null, null)
       sourceList.add(source)
    }
mPlayer!!.prepare(ConcatenatingMediaSource(*sourceList.toTypedArray()))

I want to repeat the source list for 10 or 20 minutes. How can I set the duration ?