Simultaneous audio sources with Tunepoint

[norberto]

I have a Tunepoint/Audio Connection Box on my '04 Megane II ST. I use it for playing MP3 stored on a USB pen.

In the meantime I would like to connect my smartphone to the Tunepoint AUX port when I'm using its GPS software, in order to get the instructions played through the car speakers. Nonetheless I also want to have my MP3 playing at the same time.

Is there any way to have both USB and AUX audio sources to play simultaneously? If not, is there any kind of device that can be assembled somehow on my car audio setup that will provide me an extra AUX connection that will play along another audio source? FYI I have a standard Tuner List headunit.