I am using a tableView with customised section titles. The core data objects are shown on a precise section depending on the value from a transient attribute called sectionIdent
you sort only based on due Date and name so the category with the oldest entry comes first.
the entries would have to be sorted based on your sectionIdentifier first
NSSortDescriptor *sortDescriptor0 = [[NSSortDescriptor alloc]initWithKey:@"sectionIdentifier" ascending:YES];
NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc]initWithKey:@"todoDueDate" ascending:YES];
NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc]initWithKey:@"todoName" ascending:YES];