Here's something I did to achieve something similiar: I found a settlement that only had one old man living there. I moved there for a while, and due to some misunderstandings, my dogs killed the old man. I then started gathering woodsmen and hunters who had fallen in forest cover, and guided them to this settlement, wich now was mine. After they settled there, they seem to keep roaming nearby and popping in and out of the settlement, lighting fires etc. They aren't much help apart from trading the occasional fur from them, but it kind of feels like my settlement has someone living there, or at least considering it their home.