This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
輖 combines 車 (vehicle) with 周, which likely provides the sound. The exact historical meaning is uncertain, but it may relate to a type of vehicle or a part of a carriage.
The kanji has 車 (vehicle) on the left and 周 (circumference) on the right. Imagine a vehicle designed to travel around a perimeter, but its exact purpose is unclear.
For シュウ, picture a shoe-shaped vehicle rolling around: shoe -> シュウ, and the vehicle 車 goes around 周.