Call file as variable from within a file

In linc you can call an .ngc file from within another .ngc file.

Is it possible to use a variable as a file name so I can use a set of numbered files, starting with 1.ngc goin on for as long as I have files?

I have found this page that does say files names can be numbers but it does not say if those can be added to an if/then loop or something similar:
http://linuxcnc.org/docs/html/gcode/o-code.html

The answer to your question is on the same document you linked to. Look at heading "6. Calling Files"

Yes, I still have some trouble reading technical english every now and then. Have got it woring, thanks!