LINQ to objects with several Ilists

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C#

LINQ

I have some objects created in my class but have more then one IList with my items from each list box. I am trying to figure out how to run one query to combine all of them and bind to a grid. Each list has a Unique ID which can then be used as part of the query. The project number is the UID which I have in my search class for each listbox. Here is the last function I am trying to build.

public void geteverythingforGRID()
{

    List<SearchClass> siList = new List<SearchClass>();
    List<SearchClass> siListREP = new List<SearchClass>();
    DataTable dtSomeOtherDTQuery = BuildEverythingGRIDTable(
              buildSaleRepQuery(), buildPMQuery());

    DataRow[] drsO = dtSomeOtherDTQuery.Select("REP <> '" + 
        String.Empty + "' PM <> '" + 
        String.Empty + "'");
        //This I can't figure out how to make it syntax correct
        //but is what I need?
    //DataRow[] drsO = dtSomeOtherDTQuery.Select("Sales_Rep <> '" + 
    //       String.Empty + "'");

    foreach (DataRow dr in drsO)
    {
         var s = from sr in siListREP
                   where sr.REP == dr["Sales_Rep"].ToString()
                   group sr by sr.REPEstimateNumber into g
                   join projmgr in siList on g.Key equals 
                         siList.PMEstimateNumber
                      orderby projmgr.PM
                      select new { projmgr.PM, projmgr.REP };

         foreach (var list in s)
         {
             gvSearch.DataSource = list;
             gvSearch.DataBind();
         }
    }
}