Irinir, a well-known conqueror residing on EU server CROM put together a nice, basic guide for factions in ROTGS, pointing out the gear dependancies, possibilities of betrayal, faction quests and Golem raid/group encounter. Check the guide in its full here, or see an excerpt below!

There’s a few factions that are not present in grasslands.

The Timarin Tigers and the Scholar’s of Cheng-Ho – These are present in Chosain only and you can get the quest started to make a choice between them right at the entrance of the playfield.

The Jhian Chi and the Insurrection – These factions are a exception compared to all the others, none of them have a enemy faction, and you are not given a quest to reach a faction speaker, you need to discover how to reach and befriend them. I advise you to do both quest lines, the jhian chi in Kara Korum (hint hint) have very interesting things to sell and the storyline is very interesting, the same goes for the insurrection in Paikang (hint again) with the added bonus of giving you follow up quests that lead to T4 raiding.