try shuffling the order:
Code:
/tar Cho'Gall
/tar Corrupting Adherent
/tar Darkened Creation
it'll target Darkened Creations if they're up, Corrupting Adherents if there are no creations up, and Cho'Gall if neither add is up. Important to note it'll shuffle through all available targets from top to bottom, so make sure you're actually looking at what you need to be before you start casting.