Override Crosstab cell value

[Cognos8]

In crosstab, I have put 1 measure and 2 dimension.. i want to show cell 4 as
cell 3 / cell1.. is it possible. LIKE BELOW

    C1                        C2         
A  4                           12
B  5                            13
C  6                           14
D   ( C3/A1 = 6/4)      ( C3/A2 = 6/4)   
E   8                            9

[Cognos8]

Can someone throw light on this??? I am in desperately need on this.