Two or more Joins at the same level in Query Object

Hi, how can I make two or more Joins at the same level in Query

dataitem(Sales_Invoice_Line; "Sales Invoice Line")
        {
            dataitem(Dimension_Set_Entry; "Dimension Set Entry")
            {
                DataItemLink = "Dimension Set ID" = Sales_Invoice_Header."Dimension Set ID";
                SqlJoinType = InnerJoin; 
                ...
            }
            dataitem(Sales_Invoice_Header; "Sales Invoice Header")
            {
                DataItemLink = "No." = Sales_Invoice_Line."Document No.";
                SqlJoinType = InnerJoin;
                ...
            }
...

because I get the following error:

You cannot combine two DataItems at the same level because unions are not supported.AL(AL0342)