Replying to Ip address stuff

alright.....so theres this really retarded kid at my school. and me and my buddies think he's faking having a girlfriend, cause nobodys ever seen her, and her myspace that he says she deleted a couple days ago looked fake, and they are always on aim at almost the same times(like he logs on, then she logs on 2 mins later, sign out at the same time) so, im just curious. Could i open a direct connection with then both, and get their ip address', and if they match, then id know theyre coming from the same computer, right?