I asked the question because it was already asked here on the forum, and I had been thinking about it. The answer from the Cs, to me, was that the "pool" that OPs go back and forth between is essentially a group soul "pool" made of "soul stuff" like all other soul groups.
All such "soul stuff"/groups has always existed, and they simply forms themselves into different groups based on the combined K&B of the soul group/stuff. Through individuated lifetimes, the group soul grows in K&B and can, at a certain point, differentiate or "split off" into smaller groups and even individuals, while always maintaining the connection to the originating group.
So basically, when we talk about "OPs" and "souled individuals", we're really talking about two different soul groups at different levels of K&B/development.
@Joe, what does "K&B" mean? I thought maybe the K can refer to Karma, but I have no idea what the B refers to. Could you explain?