A hard liar/truthteller type puzzle

[dvsfun1]

There is an accurate method for determining like pairs. Take any random pair and ask each one if the other is the same as him. The only time you will get a yes-yes answer is if they are both knights, or both lying spies.
The problem I'm having is although the knights will readily pair off, the spies will most likely opt to conceal themselves by giving no-no or yes-no answers; in an attempt to make you waste your questions.
Maybe someone can come up with a way to either isolate the pairs outright, or by remixing and cross referencing a sampling of isolated pairs.
I think there is a way here to positively identify a knight.