Complex sentence: Initially his duties involved overseeing the Kashrut in Tel Aviv, a position which he held jointly with Grand Rabbi Shemuel Eliyahu Taub of Modzitz (Hasidic dynasty).
Split into simpler sentences: Initially his duties involved overseeing the Kashrut in Tel Aviv. A position which he held jointly with Grand Rabbi Shemuel Eliyahu Taub of Modzitz (Hasidic dynasty).