Hierarchical List - display and behaviour query

I want to put this in Smartsheet and use the expand and collapse capability. However to get the indented list I need the name and number in the primary data column in SS. That is fine but when I export back to excel I will then not be able to know the 'parent' of an item or its level. The simplest thing would be to do as I have in excel and use separate columns for the names and use the primary data column to hold the numeric Id; however SS, unlike Excel, won't (I think) allow the contents of a cell to spill across an adjacent cell even if it is empty .

Can anyone think of a way I can acheive what I want, these are the important things:

1. a hierarchy list
2. parent is identifiable
3. indented
4. names entirely visible
5. expand & collaspe
6. exportable to excel - with parent & level characteristics that can be interrogated and manipulated

If it were only me I would be able to use just SS but I have to supply to others in the business in a form where they can extract the information.

Thank you................................ liz