This was a while back and I'm no longer able to play Arma (selling my PC) but I did actually manage to get it to work reliably. I think the trick was making sure it was only executed server side and not globally, then globalising the variable from a script running only on the server (as the ALiVE guys suggested). Feel free to have a dig around my group persistence script to see how I did it if you need clues. Specifically, I remote exec this script just on the server and it saves, loads and globalises a variable. Good luck!