yeah on the surface it does seem strange, however its actually quite normal in the agriculture space where Im working to develop this platform out.

For example, we have "farm managers" that are actually members / associated with multiple farms. One Farm manager that helps manage multiple farms owned by different organisations.

BTW most of these farms are SME style farms, and thus dont have their own domain and thus dont have unique first.last@uniquedomain.com email address. As a result, users use their personal email address to access the system.

But yes, Need to have a one user to many organisation structure.