LINQ: Group Join example

Dim obj = From a In odb.Table1
Join pm In odb.Table2 On a.SysID Equals pm.PSystem_Dept
Group Join sgs In odb.Table3 On sgs.PM_No Equals pm.PM_No Into tms = Group
From t In tms.DefaultIfEmpty()
Where (a.SysID = ddlSystem.SelectedValue)
Select New With {
pm.PM_No,
pm.PM_Title,
pm.PM_Descr,
pm.CreatedOn,
pm.Done,
t.SGS,
t.SGS_Notes
}