When an indefinite pronoun renames one noun, use a comma.
...He saw several books, none of which interested him.
...We looked at three models, each of which had some interesting features.
...I talked to the kids involved, all of which told the same story.
When an indefinite pronoun renames several nouns, use a dash.
...He saw books, pamphlets, and magazines -- none of which interested him.
...We looked at a Ford, a Toyota, and a Honda -- each of which had some interesting features.
...I talked to John, Heather, and Alicia -- all of which told the same story.
Happy punctuating!
Margie