Charles Ellicott Commentary 1 Chronicles 23:11

"And Jahath was the chief, and Zizah the second: but Jeush and Beriah had not many sons; therefore they became a fathers` house in one reckoning." — 1 Chronicles 23:11 (ASV)

But Jeush and Beriah had not many sons. — Now Jeush and Beriah had not multiplied sons; so they became (one) father-home (bêth-âb), one class (or muster—pĕquddâh). Altogether, then, there were nine Gershonite clans: namely, six of the sons of Laadan, and three of the sons of Shimei, among the 24,000 Levites of 1 Chronicles 23:4.