Problem with grouping..in reports

[vsap]

Hello Guys,
I just have an issue,I have report to be shown below:

COL1         COL2      COL3            COL4
-------- -     -------  ------          ---------
AA                  1        mycol1        genes1
                               mycol2         genes2 
                                                  genes3
                                                  genes4

                       2         mycol1        genes1
                                  mycol4        genes22
                                  mycol11      genes23
                                                     genes29
Where Col1,COL2,COL3 are from table a. and col4 is from table 2 and join is on
tablea.col1 = tableb.col1
and tablea.col2 = tableb.col2
I have grouped all columns in record source of the report.
BUT I M GETTING:
                 COL1  COL2  COL3        COL4
             --------- ------- ------- --------
                AA            1     mycol1   genes1
                                                    genes2
                                                    genes3
                                                    genes4

                                     mycol2      genes1
                                                     genes2
                                                     genes3
                                                     genes4

                            2         mycol1    genes1
                                                     genes22
                                                     genes23
                                                      genes29

                                      mycol2      genes1
                                                      genes22
                                                       genes23
                                                      genes29
...........and so on .its getting cartesan product which user dont want.

in my report i have done sorting and grouping on COL1,with COL1 header
COL2 header and then details where it shows my COL3 and COL4.So anyone can tell what should i do to get the result as it mentioned above .

Please help me out asap.

Thanks
Vsap