A hive’s lineage stems from their mother queen or empress. The lineage acts as the unique identifier and “call sign” for a hive and its members.
A lineage can only hold 8 members, this means one lineage can only hold 8 queens / empresses. Any produced afterwards create a “Rival Family.” Resulting in an entirely new lineage being created.
A hives lineage allows players to use commands from a distance as long as they have the string saved, but also allows the server to identify one lineage from another. For example. A command using it is, /avp_alien hive supply biomass <lineage_id>.
For example, say you have three hives. One hive has just developed a Harbinger before the rest and all are different lineages. From this, the game can ensure that only THAT hive can use that Harbinger for production of scourge jelly, raiding and defence. However, in the case of an Empress the lineage is shared, allowing these to actually be shared across hives.
Two lineages meeting at the borders of their “empires” will begin a war. It can also be recognised as a “Hostile Takeover” or an attempt of one at each other. Two hives from the same lineage will never go to war. Similarly, Empress hives of two different lineages that meet will still go to war as the same process but at a much larger scale due to supply lines and overall hives.