You need to create some sort of data structure, instead of trying to "store" sprites.
What matters is the logical object the sprite represents.
You can then, instead of using several sprites, use only a single Sprite with multiple animation frames (or animations).
You should then have a multiple dimensions array which X will represent the "index" for each object, and the values on Y will represents parameters/properties of the object, for example, the animation name to use in the Sprite object type to display the logical object.
One of the Y value should be either 0 or 1, 0 means the object hasn't been found, 1 it has.
When initialising your array, you should set the maximum Y (Height) value possible right away.
Even if you are not filling it right now (the default value of "empty" cells is 0 so it still contains a value).
Resizing the array "on the fly" in Y risks of losing existing values and can actually be a logical nightmare to implement.
If that did not help, consider posting your capx and explaining clearly what you are attempting to do, what you have done so far, and what you experience and how it differs from what you would expect.