problem with model design

[meri]

Hi all,

I need to make a lot of reports that look like this:

                           number of enrolled           number of canceled
faculty1     year1      x (enroll date = year1)      y(cancel date = year1)
faculty1     year2      z                                   z
faculty2     year1      b                                  t
faculty2     year2      z                                  b

My model looks like this:

fact table - students
dimension - enroll
dimension - cancel enroll

But now, I have trouble grouping data by years (since once is enrollment date, and in other case canceletion date).

How should I make my model?

Thnx,
Meri