Any way to tell Quicksilver to ignore an external h/d?

If I haven't used Quicksilver in a period long enough for my external h/d to spin down, I experience a delay as Quicksilver waits for the drive to spin back up. My external h/d is strictly backup (a nightly sync via SuperDuper) and I'd rather that Quicksilver completely ignore this drive (just like I've configured Spotlight to exclude it).

Is there anyway to do this?

thanks.