Grouping by hidden column

[fulekia]

Is it possible to group rows in a list report by a particular column, but not actually display the values for said column? I've tried just setting the item to not render, but that destroys the grouping. Redefining the data item expression to something empty/generic also flubs the grouping (as the values are no longer distinctly group-able). Even wrapping HTML items with display styling didn't work.

Example: I have a list report of classes taught by each professor in a given semester. It's currently grouped by department and professor. Some courses are cross-listed (same class, counts for different departments), so they share a cross-listing code (e.g., A, B), and I also want to group by that. See below:


Department: Neuroscience
  -----------------------------------------------------------------------
  | Professor Xavier                                                    |
  |=====================================================================|
  | Cross Listing | Course Title                    | CRN | Hrs | Seats |
  |=====================================================================|
  |               | NEU101: Intro to Mind Reading   | 537 |  4  |   18  |
  |       A       | NEU112: Basics of Telekinesis   | 873 |  4  |   10  |
  |       A       | PSY112: Basics of Telekinesis   | 877 |  4  |   10  |
  |       B       | NEU220: Public Speaking         | 632 |  2  |   20  |
  |       B       | ENG220: Public Speaking         | 633 |  2  |   20  |
  |               | PSY301: Ethics of Precognition  | 545 |  4  |   12  |
  -----------------------------------------------------------------------


Whereas desired output would look something like this:


Department: Neuroscience
  -----------------------------------------------------------------------
  | Professor X.                                                        |
  |=====================================================================|
  | Course Title                                    | CRN | Hrs | Seats |
  |=====================================================================|
  | NEU101: Intro to Mind Reading                   | 537 |  4  |   18  |
  |---------------------------------------------------------------------|
  | NEU112: Basics of Telekinesis                   | 873 |  4  |   10  |
  | PSY112: Basics of Telekinesis                   | 877 |  4  |   10  |
  |---------------------------------------------------------------------|
  | NEU220: Public Speaking                         | 632 |  2  |   20  |
  | ENG220: Public Speaking                         | 633 |  2  |   20  |
  |---------------------------------------------------------------------|
  | PSY301: Ethics of Precognition                  | 545 |  4  |   12  |
  -----------------------------------------------------------------------


Is there any way to group the A's and B's visually, but not actually print out that value? They are meaningless outside of the database, and confuse faculty who have never seen them before. Reading the conditional formatting docs hasn't immediately given me ideas regarding how to create conditions on things that aren't there, if that makes any sense. I'm sure I'm just not thinking about this the right way.

[MDXpressor]

Hi fulekia,
I think you could do this in a crosstab.
CRN, HRS, SEATS go in the columns
Cross Listing goes in the rows. 
Right click Cross Listing and choose Select Member Fact Cells
Set the bottom border to be the dashed line
Drag Course Title and nest it beside Cross Listing
If you need your dashed line to continue under your Course title, use Crosstab spaces (no fact cells) to create a separation, or to attach borders to so they are repeated for every title.
Lastly, hightlight Cross Listing in the rows, and set its Box Type to 'none'