What is a group of Sirens called?

A group of sirens is commonly called a Peal. Other collective nouns you may see include Nuisance and Sizzle.

A collective nouns for sirens is a chorus. This term superbly captures the captivating performance compelled by a group of sirens. Originating from Greek mythology, these half-bird, half-woman mythical creatures possess enchanting voices that enthrall sailors, luring them towards rocky shores and their imminent doom. Described as a collective noun for sirens, a chorus perfectly depicts the synchronized and harmonious ensemble of their voices, emphasizing both their mesmerizing song and their ability to work together. Together, a chorus of sirens bewitches any passersby, seizing their attention and attracting them to their perilous fate with their ethereal and alluring melodies. This collective noun encapsulates the communal aspect of their allure, as the sirens work in unison to ensnare unsuspecting victims with their enchantment.