I am also interested in what mechanism people and demons who are constantly in free relationships have, how they live from a spiritual point of view. Is it possible that some have a mechanism for forming a group or clan?
I do think that a practical reply is needed here, rather that theory. I'll try to speak by experience, even if mine may be limited knowledge.
As far as I have seen, relatioships (love, friendship, cooperation, ertc.) do base on spiritual connections, most often. I noticed that the deeper is the relatonship, the more and stronger cords are attached from your chakras to others' chakras. This creates a spiritual connection between two people, the stronger is love or family relarionship. This way there will be a subtle exchange of energies between two souls, so people may start feeling closer to a person, because of (slightly) common vibrations they share when interacting.
The comes will. In a relatioship I noticed that the will of a person may influence more effectively people who are closer to you, for reasons that are unknown to me. The higher influence is that of the one who is higher in hierachy, or position, whose will is steering others' wills to the group aims. I do not know how it works in Astral terms, but I oserved that.
This is what I can contribute to say, coming from years of observing fact, rather than wondering about how it is supposed to work.
Hope this helps,
