I found this in the docs
About the:
FSIN_4LANE - 4-lane MIPI FSYNC signal input/output
If I use a raspberry pi pico and program is to send pwm signal for 60 fps to pin 6 using the PSRBS cable and connect gnd to gnd, that would drive all four cameras if I set there frame sync mode to INPUT for all connected cameras? Is it true?