How Do I make the internal speakers work with a headset plugged in? iOS

Hello Unity developers, Thank you for reading my question. Hopefully you can give me some guidance.

I have an iOS game that controlled by an external mic. I want the internal speakers to work while the external mic is plugged in.

I read that this function can be done in xcode via avfoundation; but I do not know/understand how to do that. Is there any way to do it with unity? (maybe something from the asset store).