Staff requested a message informing them of the person they are trying to call is also trying to call them in place of the current call flow. And/or an option to connect to each other once one/both are informed they are attempting to call each other and accept the incoming call.

Both users hear "xxx is calling you, connect call?".

If one staff says NO the call does not go through - "xxx is not accepting the call" then follow call flow for not accepting calls.