What is the ruling on praying Sunnah in congregation?

Supererogatory prayers (Nawafil) are of two types: those for which congregational prayer is Sunnah, such as the eclipse prayer (Salat al-Kusuf), the prayer for rain (Salat al-Istisqa), the Tarawih prayer, and the Eid prayers; and those for which congregational prayer is not Sunnah and are performed individually, such as the regular Sunnah prayers (Sunan al-Rawatib) and absolute supererogatory prayers (Nawafil Mutlaqah).