Enterprise/Business Tier Ask: Create an admin toggle that allows Organizations to own all accounts under their given domain. If anyone in the future then signs up for an account with an email account in the domain, they are automatically merged into the designated Organization.
Example: Google Inc. creates a Text Blaze Org, and owns the google.com domain. Another Googler one day signs up for an account with their @google.com email address. This Googler is then automatically absorbed into Google's Text Blaze Organization.
Dropbox Enterprise offers a great example of how to execute this functionality: