The condition "Pick by UID" does the picking. The actions then does the logic (in that case indeed, destroying the picked instance).
In the game you want to make, instead of destroying you'll rather want to set the sprite invisible (as in your HUD the number of elements will be fixed and always appearing at the same position, so spawn them on start of layout and use the dictionary to keep the UID of each HUD instance you need to change the state during gameplay.
I figured since Kyatric helped point in the right direction, that I would share how I implemented the use of a dictionary. Perhaps someone will find this useful as I did :)
I simplified it best I could:
-Player can collect set number of items statically placed on level by colliding and setting item invisible. -HUD shows number of items collected (in animation form) -Collide with enemy and last item collected is taken away and set visible AND HUD will take away last collection as well
Link to file - http://dl.dropbox.com/u/58760772/itemCollect.capxfacecjf2013-01-24 14:41:05