This attribute allows the peer group id of the Logical Group Node
(LGN) to be set. The peer group id is specified by 28 hex digits
where the first octet represents the level of the node and the
remaining 13 octets form the End System Address. If this attribute
is set to the null string then the peer group id is computed as
follows:
The peer group id for a lowest level node is computed to be the
node's level (one octet), followed by the first <level> bits of the
node's address, followed by zero or more padding 0 bits.
The peer group id for an LGN is computed to be the LGN's level
(one octet), followed by the first <level> bits of the id of the peer
group which this LGN represents.