An entry of the hh3cMDCGroupIfTable, every entry is the relationship
between interfaces and groups.
Due to hardware restrictions, the interfaces on some interface cards are grouped.
The interfaces in a group must be assigned to the same MDC at the same time or
removed from an MDC at the same time. Interface grouping depends on the device model.
This table is used for hh3cMDCAllocateTable to show interfae group lists.
Note that only entPhysicalIndex values that represent
physical ports (i.e., associated entPhysicalClass value is
'port(10)') are permitted to exist in this table.