Can I also add that it might be best even if you do have the option eventually not to have writers working all at once? The only reason I 'm giving my two cents is because I've been a writer on a project where several writers were working toward one end, and it got very messy very quickly. If it's something like a blog, it could work, where writers are making individual changes. But if it's something like a script, you would want to have meetings where each writer discusses what changes they will make, or give each writer a turn at the draft. This will work out much better for you in the long run and eliminate potential confusion and hurt feelings among writers.