[Icecast] can I convert ogg to mp3 streaming on fly?

[Simone Dal Maso]

Hello,
I am configuring a webradio and I'm using icecast2 with deefuzzer.
the music streaming work, in mp3 format.
I want to make a second streaming with my iphone, and the app that I'm 
using, Koalasan,  can stream only in OGG, AAC or Opus.
I want that when I start speaking, music stops and my voice is online.
Deefuzzer is able to do this with "relay", but the original stream in 
mp3, and the stream from my iphone is in ogg.
do you know if I can convert the ogg streaming to mp3 and then pass it 
to icecast?
is it possible?
thank you.