If you have access to a Death Note, know the rule that four unintentional misspellings result in immunity to the Death Note, and are hunting someone with a Death Note, couldn't you trick someone you gave the Death Note to misspell the names of everyone in your task force four times?
I know nobody got a chance to do this in the anime, and probably not the manga either, but this still seems the obvious method of setting up a Kira task force: make the members immune to the Death Note without telling anyone, putting Kira in the dark in a way that gives you a significant advantage.