Do you want to display in each sublevel the same records from table2?
In that case you can specify in FlyGrid.Rows.DataSource your dataset that contains these tables, in FlyGrid.Rows.DataMember - the name of the table1, and in FlyGrid.Columns.NestedDataMember - the name of the table2.
Don't forget to initialize the root columns (FlyGrid.Columns)and nested columns (FlyGrid.Columns.NestedColumns) to correctly display data.