4 A larger number of leaders were found among Eleazar’s descendants than among Ithamar’s, and they were divided accordingly: sixteen heads of families from Eleazar’s descendants and eight heads of families from Ithamar’s descendants.

Read 1 Chronicles 24:4 Using Other Translations

And there were more chief men found of the sons of Eleazar than of the sons of Ithamar; and thus were they divided. Among the sons of Eleazar there were sixteen chief men of the house of their fathers, and eight among the sons of Ithamar according to the house of their fathers.
Since more chief men were found among the sons of Eleazar than among the sons of Ithamar, they organized them under sixteen heads of fathers' houses of the sons of Eleazar, and eight of the sons of Ithamar.
Eleazar’s descendants were divided into sixteen groups and Ithamar’s into eight, for there were more family leaders among the descendants of Eleazar.