Is it permissible to lead or supervise those in I'tikaf during their I'tikaf?

Itikaf (seclusion for worship) is a Sunnah firmly established by the Qur'an and Sunnah. There is no evidence that appointing someone as a leader over those observing Itikaf is a Sunnah or required. However, there is no harm in agreeing to appoint a supervisor to manage the affairs of those observing Itikaf, such as matters of food and drink, if they need it. As for what was narrated from 'Umar ibn al-Khattab: "If you are three, then appoint one of you as your leader," this applies specifically to travel.