I have a few phones in my office and one of my employees is out. I have all the lines set to BLFs on the right side of the desk phone LCD screen which are GXP2170s. When ever someone is receiving a call, everyone can see the employee’s line ringing. I want to be able to hit the button for that employee’s line and answer their call at my desk. Which line type do I select, or how do I set this up? Thank you.