Is it possible to connect two bluetooth devices as a headset to the phone?

Question

Android

I want to make an application for myself, such as a walkie-talkie, to connect two bluetooth headsets to the phone and communicate with each other + be able to put on music when there is no one to communicate with.
For music, a2dp is used, but it does not seem to work as a headset (microphone).
To talk on the phone, hsp is used.
It is not very clear which profile should I use and is it possible to do this?