A computing device includes a processor is programmed to determine that communications from users relate to the same subject included in a stored list of subjects. Each of the communications includes an audio portion. The computing device is further programmed to determine a score for each of the communications based at least in part on one or more of tone data, speed data, duration data, and volume data extracted from the respective audio portion, and allow one of the users, based on a respective user score, to assign the subject to a group.