TR_VENDOR_INSERT_UPDATE_ISGROUP

          CREATE trigger TR_VENDOR_INSERT_UPDATE_ISGROUP on dbo.VENDOR after insert,update not for replication
          as begin
            if exists(
              select C.ID
              from INSERTED I
              inner join CONSTITUENT C on I.ID = C.ID
              where C.ISGROUP = 1)
             raiserror('Constituents that are groups cannot have vendor information.', 13, 1)
          end