Faction system I can hack into a WWN/OSR game

I was thinking about a campaign idea, loosely based on The darkening of Mirkwood, where players play as characters through decades, while building their families, clans and towns, claiming the dark forest and purging it from evil. Each player controls his clan during downtime. And a lot more, but that's not relevant now. I was thinking about using Worlds without number. I was intrigued by the clan-building thing and I was thinking about using the faction system, but I'm not sure if that can be used by players.

Is there a system that have factions played by players that I can hack and use with the WWN core system?