Check the state of every instance

How can I check that every instance of a sprite is invisible?

Or,

How can I check if every instance of a sprite is destroyed?

for each sprite - sprite is invisible add 1 to variable.

And to see if they are all destroyed

system compare two values - sprite.count = 0

so if sprite.count is the same as the variable, all sprites are invisible.

All sprites destroyed:

<img src="https://dl.dropboxusercontent.com/u/8367729/construct/pics/allSpritesDestroyed.PNG" border="0" />

All sprites invisible:

<img src="https://dl.dropboxusercontent.com/u/8367729/construct/pics/allSpritesInvisible.PNG" border="0" />