And Shemaiah the son of Nethaneel the scribe, one of the Levites, wrote them before the king, and the princes, and Zadok the priest, and Ahimelech the son of Abiathar, and before the chief of the fathers of the priests and Levites: one principal household being taken for Eleazar, and one taken for Ithamar. (1 Chronicles 24:6)
The list appears in vs. 7-18. There seems to be no means by which it may be determined to which of the lines individual clans belonged, whether to Eleazar or to Ithamar.