Crystal Reports Calculated Member in Crosstab

Message

     I have a crosstab in my report, and I would like to do a calculation for every two columns, and have that result appear as a row item below the totals.

So my columns are like this: Jan 2008, Jan 2009, Feb 2008, Feb 2009, etc.

I want to divide the total under Jan 2009 by the total under Jan 2008 to get the percentage of difference from one year to the next, and I'd like that percentage to show under the totals in the following row.

Jan 2008               Jan 2009
total                      total
% difference          .85

I figure that's the easier way to do it, but I'd like it if it could actually come out like this:

Jan 2008               Jan 2009
total                      total
           % difference
                 .85

where "% difference" and ".85" are in one field each that is the length of two columns.

Right now the best I'm able to do is to add a calculated member and have a column put in between the two columns I'm calculating, but that's not what I want it to look like. I have details under the totals (a total for each customer), but I don't need those individual percentages calculated- just the totals for each month.

Thanks for the help!