Switching Output of mp3 Player

I am working on a home project where the goal is to switch one channel of an mp3 player periodically to 4 different speakers, one at a time. I envision using a periodic audio frequency pulse on the other mp3 player channel to trigger the switching. In this case I would record sounds of nature (owls, birds, thunder, crickets, etc on one track. Between each segment I would record an audio tone when I want to switch to a different monaural speaker. The same rotation of speakers would always be used although it would be nice if a random rotation could also be selected.

If you're not switching power just signal a simple analog multiplexer could easily switch 4 channels or more. The audio signal itself doing the switching is not quiet as trivial as you have to guarantee the audio you want to play does not switch it as well, and the audio trigger will likely be audible. A simple tone decoder could be used to increment a counter which would control the multiplexer.

And I'm sure someone makes "clickless" IC switches for this type of application.

Maxim makes a "clickless" audio multiplex IC. It waits a moment then switches at the zero-crossings of the existing channel and the new channel.

Years ago I switched audio by ramping down the volume, switching in silence then ramping up the volume.