Pretty sure that vanilla OFPR's scripting language has no convenient way to turn strings into arrays.
If there is I'd love to hear about it.
Are you just trying to save typing, or do you want strings to be turned into arrays while the mission is running?
If it's the second thing, and if the string to be turned into an array contains only a few characters, then you could write a .sqf that finds what series of characters can be added up to produce the string. If you're interested, maybe I can type up what I have in mind.