>>Also, what do I need to use to flip it other as the next loop does the following:
>>
>>

>>  // Add New List
>>                foreach (var item in modifierGroup.Items)
>>                {
>>                    if (!itemIds.Contains(item.ItemId))
>>                    {...
>>
>>

Maybe:

foreach(var i in modifierGroup.Items.Where(x=> !itemIds.Contains(x.ItemId)))
>            {
>                // Use i (or i.ItemId) here
>            }

Thanks again, it worked quite nicely.