How to prevent dragging into a list by type

[zippy]

Hi, I'm trying to use this library and I have two DragDropLists of different typeson the same page, and I can't figure out how to specify that I shouldn't be able to receive items from a different list type. I can make it not accept them on drop, but I'd like the list to not even receive it on drag over. How do I specify that?

Thanks.