Does Apple charge fees on money that our users are earning?

I am developing a paid video chat app. Users can charge their callers $x/minute to video chat with them (Celebrities, experts, anyone with a fan base). We will be taking a 5% fee from money earned on the app.

Will Apple take its fee on all transactions on the app? For instance if a user earns $1000, do we need to pay Apples 30% fee on that $1000, even though that money is not ours. It is being paid out to the user.

If Apple takes its fee on all transactions made on the app, it makes it cost prohibitive. I can certainly understand Apple taking its fee on money we earn though.

Does anyone know Apples terms regarding this?

Thanks!