This looks more like something that could be created with a tree view widget, have you seen this: https://appstore.home.mendix.com/link/app/112707/
Could also be done with listviews within listviews and using groupboxes for the collapsing, this will probably need a lot custom css to style.
Hi Tjark,
I did this once on project where my users were real Excel tigers.. This is how it worked out:
Templategrid header:
Template grids with a _Expand boolean attribute on the shown entities (default false) which could be toggled with the chevron up/down to show or hide the organisational units. This way a user could drill down from Enterprise KPI's al the way to Business Units KPI's.
Just plain Mendix always works best for me. :)