Prayer: The Gap When Linked to the Imam from the Side
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1416
If a follower is linked to the imam by a person on either his right or left side and he is not linked to the imam from the front, then based on obligatory precaution, there must not be a gap of more than a step [as defined in the previous ruling] between himself and the follower on his right or left side.