Because sometimes what you select to download ends up not being available or if you have to resume at a later time and it can't find that particular instance of a file, people may select multiple instance of the same file.

If you could select multple download requests and 'link' them or marked them 'associated' or 'similar' then whichever one finishes first it could automatically cancel all the other linked requests.

Does this make sense?

Gryffyn