Views - How to display results in nested groups?

Question

I have a View listing out members of staff. Each staff member belongs to a department, or sub-department. I want to list out all staff members but group them under their (sub)-department in a nested manner. For example:

# School Board
John Doe

# Teaching Staff
Jane Doe

    ## Chemistry
    Eric Betzig

    ## Physics
    Shuji Nakamura
    Isamu Akasaki

I know you can use the Group by Fields option, as described in this answer, but it doesn't allow for nesting:

# School Board
John Doe

# Teaching Staff
Jane Doe

# Chemistry // Not nested
Eric Betzig

# Physics // Not nested
Shuji Nakamura
Isamu Akasaki

Answer 1

I think this is more a question of styling than views itself. You could assign a class to the row output (e.g. with a replacement pattern token or something) and then style the css to show the output "nested".

Answer 2

I ended up using the Views Field View module.

The logic is as follows:

1. Create a View listing out the terms (I call it the 'Tree View')

   # School Board
   # Teaching Staff
   # Chemistry
   # Physics
   

2. Create a View which takes a Contextual Filter of Content: Has taxonomy term ID and display all content with this term ID. (I call this the 'Content View')

   ## Physics
       Shuji Nakamura
       Isamu Akasaki
   

3. We have the building blocks, now let's combine the two Views together. In the 'Tree View', add a relationship with the Parent term (Taxonomy term: Parent term) and add (Parent) Taxonomy term: Term Name to the fields. Now go to Format > Settings and Group the result by (Parent) Taxonomy term: Term Name and check 'Use rendered output to group rows'

   # School Board
   # Teaching Staff
       ## Chemistry
       ## Physics
   

4. Still in the 'Tree View', add the (Parent) Taxonomy term: Term ID and Global: View fields. In the settings, under View, select your 'Content View', and under Contextual filters, put [!tid] in order to pass the term ID to the 'Content View'. And we are good to go!

   # School Board
   John Doe
   
   # Teaching Staff
   Jane Doe
   
       ## Chemistry
       Eric Betzig
   
       ## Physics
       Shuji Nakamura
       Isamu Akasaki