I'd like to know if a woman can be as an Imam al-Jama'ah in Wajib (mandatory) prayer? (actually can she be as the imam al Jama'ah of other women?)
(Note: I am looking for Shia viewpoint)
The consensus amongst Muslims (Sunni and Shia) are both that woman are allowed to lead woman only prayers, even if they are wajib. The Difference of opinions started to diverge as for mixed gender prayers.
As for Shia, it was banned for a while until it was unbanned by the majority in the year 2000.
Three of the four Sunni madhhabs—Shafi'is, Hanafis, and Hanbalis—allow this, although Hanafis consider it to be makrooh, a disliked act. (The fourth division, Malikis, do not permit women to lead women in prayer.)
In 2000, six marjas among Iran's Shia leadership declared that they too allowed women to lead a woman-only congregation, reversing a previous ban in that country.