A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
1. I may have a folder called Sales opportunities, a different folder called customer, a different folder called past customers. (This would be at the top level)
2. Next I would have a sub folder for each opportunity or customer by name. (this is the 2 level)
3. Next I would like to have individual notes for each meeting with a customer. (this the 3 and final level)
I would have a single notebook, with 3 section groups: Sales, Customers, Past customers.
Each section group has a section for each opportunity / customer.
Each of these sections has a page for each meeting.
As BenRG pointed out, section groups are completely recursive: they can contain other section groups, which in turn can contain section groups, and so on. But you don't need this for what you want.