A Simple question about Dataet with mutitables

[Ing. Rajesh Kumar]

Hi Everybody
I have three tables USERS, ROLES and GROUPS in a SQL Server. As you can
guess, I am using these tables to check permissions. Now I converted these
SQl tables into XML tables and put them into roles.xml and created an
roles.xsd with PK's and FK's. For testing I can load this file into a
Dataset and then display the tables into three different DataGrids. Now I
want to get one table based on the combination of these three tables. The
following command is equivalent in SQL Server.

SELECT * FROM TABLE1, TABLE2, TABLE3 WHERE TABLE1.ID = TABLE2.ID AND
TABLE1.GROUPID = TABLE3.GROUPID

So how can I combine the tables DS.Tables("users"), DS.Tables("roles"),
DS.Tables("groups") ?

Probably it can be done by using DataViews but cannot find out how. A good
example or good link will be very helpfull.
Thanks in advance
Raja