drag-and-drop-translator exclude reflexivity

[Kilian Sprotte]

Hi,

do you know how it is possible to extend
the following definition of a drag-and-drop-translator
so that it is not possible to link items with themselves?

(define-drag-and-drop-translator connect-items
    (item command item command-table)
    (object destination-object)
  `(com-connect-items ,object ,destination-object))

Regards,
Kilian