Is it possible to exchange data between devices so that this exchange is not detected?

Question

Bluetooth

Good afternoon.
I want to write a mobile application.
Is it possible to exchange data between devices through these applications in such a way that this exchange is not detected?
Data exchange is carried out, for example, via Bluetooth.
Simply put, it is necessary that these applications find each other on different phones. They paired, exchanged data and did not visually affect in any way.
This requires that other applications do not detect pairing and exchange.
PS on security issues: data exchange is planned to be carried out strictly within the framework of these applications.
PPS if this is not feasible, then is it possible to get some kind of identifier for a phone that is in the Bluetooth access area. Those. so that both phones find each other, get each other's identifiers. And the data exchange will already be done via the Internet.