How many is a sufficient number to perform the communal obligation (fard al-kifaya) in following a funeral procession?

Following funerals is one of a Muslim's rights over his brother, and it is recommended, carrying immense reward. Some scholars have held that it is a Sunnah (prophetic tradition), while others have maintained that it is Fard Kifayah (a collective obligation), meaning its obligation is lifted if performed by even one person, similar to the funeral prayer. Nevertheless, the call and encouragement to participate in it do not cease for those who are able, as it remains a right of a Muslim over his brother.