How can I set a specific dropArea for my drag in qml?

[sq-a]

I want to drag my qml widget and drop it on a specific droparea(I will call it "specificArea".)

There are private infomation on 'Drag.source', I want nobody can accept drop but the specificArea.

But I can't prevent any other dropareas or other programs like notepad accept drops.
I used Drag.keys or mimeData, but it filtered the drags that dropArea can accept. It didn't filter dropares that drags can drop.

Is there any solution for this?
If I am asking wrong question, please let me know.