CREATE #tbGroup

MERGE tbGroup -- в 2 стороны: INSERT, DELETE
...

INSERT #tbGroup
FROM tbGRoup
WHERE ...

--пляски с использованием tbGroup.Id и не только

--сохраняем данные из кучи временных таблиц, у которых в том числе есть ссылки на tbGroup.Id, в постоянные
BEGIN TRAN
--ЗАБЛОКИРОВАТЬ tbGroup от удаления строк
DELETE tg -- + каскадное удаление из всех дочерних временных таблиц
    FROM #tbGroup tg 
    LEFT JOIN tbGroup g WITH(UPDLOCK) 
        ON g.Id = tg.Id
    WHERE g.Id IS NULL

MERGE 15 штук ...

DELETE 
FROM tbGroup tg 
WHERE ...

MERGE 15 штук ...

END TRAN

select count(*) 
from tbGroup with (updlock, <подсказка для блокировки по диапазону ключей индекса>)
where OrgId = @OrgId

<подсказка для блокировки по диапазону ключей индекса>)

select count(*) 
from tbGroup with (INDEX(IX_tbGroup_Orgid), updlock, rowlock)
where OrgId = @OrgId

BEGIN TRY

 ALTER TABLE tbGroup SET LOCK_ESCALATION = DISABLE 
 BEGIN TRAN
 ...
 END TRAN 
 ALTER TABLE tbGroup SET LOCK_ESCALATION = AUTO

END TRY
BEGIN CATCH
 ...
 ALTER TABLE tbGroup (SET LOCK_ESCALATION = AUTO
END CACTH

DELETE tg 
FROM #tbGroup tg 
LEFT JOIN tbGroup g WITH(UPDLOCK, INDEX = IX_tbGroup_OrgId)
    ON  g.OrgId = @OrgId
	AND g.Id = tg.Id
WHERE g.Id IS NULL   

SELECT COUNT(*) 
FROM tbGroup g WITH(UPDLOCK, INDEX = IX_tbGroup_OrgId) WHERE g.OrgId = @OrgId

SELECT COUNT(*) 
FROM tbGroup g WITH(UPDLOCK, INDEX = IX_tbGroup_OrgId)

tbEventCalculationList 
(id int identity(1, 1), 
EventId int not null,
DataFormingDate datetime not null)

    INSERT tbEventCalculationList WITH (UPDLOCK, HOLDLOCK, INDEX = IX_tbEventCalculationList _EventId)
    (EventId, DataFormingDate) 
    SELECT EventId, DataFormingDate
    FROM #tbEventToGroup

Index hints are only allowed in a FROM or OPTION clause.