en_tn/neh/12/09.md

Bakbukiah ... Unni

These are names of men. (See: rc://en/ta/man/translate/translate-names)

stood opposite them during the service

Possible meanings are 1) this was during a worship service and these were two groups of singers or other worshipers, or 2) these groups guarded the temple at different times, or "took turns guarding the temple."