Collapsible columns / "subcolumns"

I’d like to be able to group columns into a group, and be able to quickly expand and collapse those groups.

My use case: we have a very large combined marketing board, with budget columns that cover multiple subsets of budget. For instance, we have a social media budget column, and several columns for different social media channels, that would fit neatly under the heading of “social media budget”.

The table has several such columns and potential sub-columns. It would be neat and easier to navigate if we could put these into groups - e.g. all the social media channel budgets under a parent group of “social media budget” - which could be collapsed and expanded horizontally. This would allow you to narrow and widen the table to the level of detail you required.