A method includes receiving a list of sequential telephone numbers, and iteratively: identifying a first number and a last number of the list, selecting a group size, creating a group of sequential telephone numbers from the list of sequential telephone numbers based on the selected group size, and removing the created group from the list of sequential telephone numbers. Creating the group may include determining whether a first number in the list of sequential telephone numbers ends with a predetermined digit, assigning the first number as a start number of the group, and identifying an end number in the group based on the start number and the selected group size.