No, they only listen to the red/green pair, so only Line 1 will show up. However, way back the first time I had D*, I used a clever little Radio Shack automatic switch that was designed to allow an answering machine to answer two lines. I just wired the jacks that the D* receivers plugged into so that they were connected to the line switch. Then when either line rang the switch would grab the ringing line and deliver the caller ID to the receivers (albeit with no indication whether it was Line 1 or 2). Now, I doubt RS still carries said switch (since voicemail has obsoleted answering machines), and the ones I've come up with searching are way more expensive than I remember it being (I think it was like $20-30). But if you can find one cheap, that's how you do it.