During Sri Caitanya Mahaprabhu's time, one (sankirtana) party was composed of twenty-one men: four people playing mrdangas, one leading the chanting, and sixteen others striking karatalas, responding to the leading chanter

Expressions researched:
"During Sri Caitanya Mahaprabhu's time, one party was composed of twenty-one men: four people playing mrdangas, one leading the chanting, and sixteen others striking karatalas, responding to the leading chanter"

CC Adi-lila

This is a scheme for performing kīrtana in a procession. During Śrī Caitanya Mahāprabhu's time, one party was composed of twenty-one men: four people playing mṛdaṅgas, one leading the chanting, and sixteen others striking karatālas, responding to the leading chanter.

CC Adi 17.135, Translation and Purport:

In the evening Lord Gaurasundara went out and formed three parties to perform kīrtana.

This is a scheme for performing kīrtana in a procession. During Śrī Caitanya Mahāprabhu's time, one party was composed of twenty-one men: four people playing mṛdaṅgas, one leading the chanting, and sixteen others striking karatālas, responding to the leading chanter. If many men join the saṅkīrtana movement, they may follow in the footsteps of Śrī Caitanya Mahāprabhu and form different parties according to the time and the number of men available.