Help needed: Drag & Drop quiz stacking items

Hi, I'm trying to create a drag and drop quiz in Storyline 360 with the following requirements:

1. Multiple drag-able items can be dropped into the same zone. 
2. Whenever a drag-able item is dropped on a zone it changes state (size).
3. Whenever multiple drag-able items are dropped on the same zone they stack up next to each other (from left to right).
4. The containers (the grey boxes behind each drag-able item) can be clicked individually to return their drag-able items to their original positions.
5. Whenever a container is clicked and a drag-able item is returned to it the item changes back to its original state.
6. If a drag-able item was returned from a zone where multiple other items were stacked up the remaining items should align next to each other (from left to right).

I have provided an example of how far I have gotten but currently I can't seem to create point 3 and 6.

Any help would be greatly appreciated.