An oversoul lineage is the byproduct of incarnation on any plane of reality that involves some form of conception. Beings involved in the creation, nurturing and development of a persons Density Interface become attached via frequencies. your biological ancestors are resonant with you to a degree, regardless of their relation to your soul.

Your ancestors could be from the same Soul Collective or even be the same Oversoul from a prior incarnation, but they can also be members of other Soul Collective groups.

much in way nations might interface via diplomacy, many soul collectives work together to achieve goals in a given plan of reality. This is especially the case here on earth, as alliances between soul collectives was on way to share resources once the quarantine fell upon earth and connection to the omnivum was deeply occluded for most beings.

as these group co-ordinate they tend to prefer to incarnate at similar times, places and even in the same family lines. One benefit of this is higher levels of co-ordination and mild resistance to density related effects

put another way it is easier to maintain stable consciousness with familiar beings around, and easier to reconnect and access higher dimensional knowledge if you incarnate into family lines your soul has been active in in the past.

these two effects combined make relations between soul collectives highly potent forms of increasing the odds of successful incarnations

but it also incurs additional resonance issues. linking soul collectives, and Individual Self members via this process increasing their effect on one another in both a positive and negative manner. there is risk of corruption spreading between lineage members, and other issues,