C# -linq to sql using a group by

I have a C# 2008 application that uses the following linq to sql statement to connect to a sql ser ver 2008 r2 database. 

   var lcount = (from iw in erptData.Ibooks
                     join ip in eData.IPackages on iw.Package_ID equals ip.Package_ID
                     join impt in eData.Import_Error on iw.Workbook_ID equals impt.Workbook_ID
                     join tt in eData.Transaction_Types on impt.Trans_Type_ID equals tt.Trans_Type_ID
                     where ip.Tracking_Number == packageId
                     group impt by impt.Contract_Number_Err into g
                     select new { Contract_Number_Err = g.Key, Frequency = g.Count() }).FirstOrDefault();

I would like the linq to sql statement to translate to the following sql statement:


select distinct(t.data_errors),
COUNT(t.Import_Error_Trans_id), ip.Tracking_Number,t.Contract_Number_Err
from dbo.Import_Error t
inner join  dbo.Ibooks iw on t.Workbook_ID = iw.Workbook_ID
inner join dbo.Import_Package ip on ip.Package_ID = iw.Package_ID
--inner join dbo.Plans p on p.Plans_id = t.Plans_ID
where ip.Tracking_Number = 'XXXXXX'
group by ip.Tracking_Number,t.Contract_Number_Err,t.data_errors

I do not know how to get the ip.Tracking_Number,t.Contract_Number_Err values in the group by statement
and in the annoymous select statement.

I would like the counts distinct by tracking number,Followed by contract number.

Thus can you tell me how to write the linq statements to accomplish this goal?