Allow to define the scope of tags/choice list custom field values (account vs. workspace)

It should be possible to define whether the values of choice list and tags custom fields (predefined or editable) are shared at account level (current behavior) or limited to workspace level such that workspaces can share a configuration but have their own pick list values. This is currently already possible for Aha! record relationships custom fields where you can choose 'Filter field values to <account/product line/workspace>', the same would be very useful for other custom field types.