To segregate our data and allocate each salesperson designated Organisations, we have split our Organisations into various Groups with each Group containing a few hundred different Organisations. Is there any way for the Admin User to view or produce a report on which Organisation belongs to which Group and view or search on which Organisations do not belong to any Group so we can allocate them accordingly?

I realise that you can go into each Organisation one at a time, and as an Admin User it will show which Group that Organisation belongs to, but this is extremely time consuming.