I'm trying to place objects in slots and then stop objects from being placed in the slot

I am very new and kind of just messing around with the software so I apologize if this is obvious.

The problem is I want to stop multiple objects from being placed on the same tile.

Right now I have all the objects in a group called Cards. Whenever a card is dropped it checks for collision with a tile if it is true it moves to the center of the tile. If it is not true it cancels the drag.

I tried to just check for collision: Cards is in collision with Cards
but then it moves the one that was placed previously
I’m assuming its a problem with choosing which objects in the group to check but I’m not really sure.

thanks

You could make additional object and call it checker
Now you could create that object where card should go

Now if that object is in collision with card you don’t move your card there
If its not you move your card there