Disable volume control from my iPhone over AirPlay?

Hi, I have my RS150b set to fixed output. I prefer to control the volume from my amplifier.

However, when I stream from my iPhone over Airplay, my phone can control the volume.

Is there a way to make the volume fixed over AirPlay?

@cblackstar7

Sorry for the late reply.

This problem is because when playing Airplay on iPhone, it is sent with the volume set low. And there is no way to fix the volume value when playing with Airplay.

Thank you