If they are all running the same script, you define a file based parameter in the script.
- highlight text to replace
- right click and select replace with a parameter
- enter desired param name
- select type 'file'
- select 'Properties' button
- enter file path
- select 'Create' button
- edit file as necessary
- select next row 'Sequential'
- uncheck advance row each iteration
Run script in controller and this should have the desired effect.