GA - Group Whitelisting Question

I know this may be a repeat of a thread elsewhere, but someone brought my attention to utilizing the group option for giveaways. How does this work? My issue is that my group "is too new" to show up on this website, but can someone explain from a technical perspective what this means? When will I be able to see my group on the Giveaways, as I'd rather use that as an option in the long run.