How do i create a collapsing/expanding list?

Hi,

Hoping someone can help me. I need to create a document that contains a number of columns, each of which contains a list of data (job titles and descriptions). I want to be able to put this data into different expanding lists within the same column.

So, a column initially displayed like this

HR
+HR Analyst
+HR Finance


can become this;

HR
-HR Analyst

- Payroll

- Admin

- Foobar

-HR Finance

- Numbers

- Pasta

I want to repeat this across each column. I've played around with the Data/Groups but this doesn't give me what i need because it collapses all rows across the workbook, rather than just the ones in the column. It also doesn't make clear which cell can be expanded.

Any clues on how i can do this?

Many thanks in advance.