oosyrag That overlapping condition doesnt work because both blue sprites are overlapping green sprites.
You have no idea of the complexity of the question you are asking xD
You want to make a connection between an instance of a green sprite and an instance of a blue sprite, so when you click on green, blue gets destroyed. Impossible.
There are a couple of ways to go around that.
1st way - as suggested by oosyrag, using containers. The problem - the green and blue sprites both get destroyed.
2nd way - use multiple green and blue sprites, so - green1, green2... and blue1, blue2..., and when
green1 clicked>>destroy blue1
green2 clicked>>destroy blue2... and so on.
There might be some clever way using instance and global variables, UID and IID, that solves your problem, but it will be hard to do.