A tool used for managing multiple auctions is presented. The tool includes instructions providing the capability of creating subgroups of auctions based on criteria used to sort data pertaining either to the subject matter of the auction or to its participants. Further, the tool manages within-group closing times by extending closing times of all auctions in the group. A comparison of a recent bid to extension criteria may extend the closing time of an auction by an extension period; if the number of times this auction is extended meets a trigger number, then all closing times of all auctions in the group are extended by a specified time related to the trigger number and the extension period.