automatic change from 50hz to 60hz when NTSC switch is on (and back to 50hz)

[mistepien]

Sometimes it is good to use NTSC variant of game. I have fs-uae-launcher in sort of "kiosk mode": it would be great if fs-uae-launcher is able to switch to 60hz automatically or by starting some script. After exiting back from emulation reverse action would be fine.