https://learn.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/get-started/grid-capabilities

D365 F&O cross-app enables users via saved views and grid control to customize their views/fields/... and save them.

Users can create pivot-like views with the group-by and Totals in all list view pages

This also works on order line forms (SO lines, PO lines, TO lines, ...) but on these forms, the group-by can't be saved.

This means the users needs to recreate their group-by every time they open a sales, purchase or transfer order