How to turn off inheritance of Report Services

Question

HI im using Sql server business Intelligence Developement Studio 2008.
My report has 3 tables, im actualy using matrix grids, 3 of them.
AmountReport as AR, CountReport as CR, ExposureReport as ER.

my dataset looks like this:   SELECT     TotalBsuUserTrendAnalysisAmountReport.*,(Users.UserNames + ' ' + Users.UserSurname) as                                                         fullname
FROM                                                 TotalBsuUserTrendAnalysisAmountReport INNER JOIN
                                                              Users ON TotalBsuUserTrendAnalysisAmountReport.UserID = Users.UserId

so the table name would just change in the from clause. all these table's have a UserID in common from a user table.

My problem is this, i need to load the content of all 3 tables by the one user ID so the reports are all individual based, and im new to report services
so I got a list = list1 which has the Fullname in it, and below that is a matrix grid, and below that the other 2 matrix grid, but they all are inheriting the same data set that
list1 is using and i cant change it. even if my list1 is on datasetname=nothing(blank) i stil cant select a dataset.

So how do i switch this inheritance from the parent off, or what should i do?

e.g

List1
|___________________________|
| [fullname]  |
|  [MatrixGrid_AR]  |
|  [MatrixGrid_CR]  |
|  [MatrixGrid_ER]  |
|  |
|  |
|___________________________