Girls aloud will split up.Its a dead cert.
When ronan left boyzone, he released his first single to test the water and see if he could go it alone. Once he had some sucess, they announced they were taking a break.
I can see the same thing happening with GA. If cheryls album is a success, they will say they are taking a break and that will be it.
Some of the others are recording solo material too, but then its whoever gets there foot in the door first usually.