I don't think there is a way to tell if you're the 1st person or the 2nd person called. Caller ID would tell which phone the "original caller" called from & make sure she's talking to that person - make sense? I remember being in middle & high school, we all had 3-way calling & would end up with 7 or 8 people on the phone. Tell her to be careful, girls can be very sneaky & mean - don't say ANYTHING that you wouldn't want someone else to know - just in case the wrong person is being quiet while on 3-way.