Ak6,
I wanted to say briefly that I've struggled with some of the same types of encounters that you describe. I came to a few conclusions. First, I think that when we have a past life connection with someone, that adds a certain feeling of "weight" to it even though the connection may not be qualitatively a good one. The sheer familiarity of it makes one feel like one should fall in love. It's a basic error in assessing the situation.
Secondly, in my case, I found that there were two reasons, apparently, why I kept having this repeat experience. The first was that I had been cruel to people in past lives, and so unconsciously I was opening myself up to predatory people in romantic relationships. And they were being predatory--but it was my past-life karma that made me susceptible. I uncovered this in a past-life regression. I saw myself sadistically figuring out ways to split up couples, because I was grieving and "misery loves company", while pretending on the surface to feel sympathetic. The sadism I let myself in for in these relationships in this life, I now saw as the *exact emotional inverse* of the sadistic pleasure I got from splitting up these couples in that past life (from quite a long time ago, I gather, because it was an advanced civilization--but these things follow you down the ages).
The final thing I realized was that apparently I was still grieving for a partner I'd lost in a past life, and so I kept trying to find her again. Instead of finding her, what I was doing was projecting my longing onto these other women, opening myself immediately (though part of myself was resisting). What I finally did was to decide that this woman I was grieving for would probably prefer I find a truly caring partner, than to keep getting involved with predatory people while trying to hang on. So, once I did that, not too long afterwards, I did indeed find my current girlfriend, and our relationship is just now going into the six-year mark. It's probably not the same relationship I had with this woman I was grieving for. It's different, like my best friend in the world, definitely a past-life connection there, but more individuated, not so much "melded together". For one thing we're so different in our interests, but there is a deep understanding there despite that.
As far as soul groups goes, I don't know. I get the sense that we have been very good friends, and then in other lives we have been lovers, but this is the first time we are really putting the two things together to form a long-term relationship.
Don't know if any of that would be relevant to you, though...
Steve S.