they have an interesting history, but historically they were fought by the byzantines and often allied with muslims in the region, while in the game afaik, this doesnt work that way. They do have a friendship with the neighbouring emirate, but often those friends go to war quite quickly.
I've been looking into it, to see if I could get them to cooperate more, but sadly the nature of the game doesnt really allow little dwarfs like this to prosper around qiants such as ERE, as they did sometimes historically.
I had an idea to change this, but i doubt that its possible to mod. I would really like to see it possible that independent counts and dukes can wage war against count and duke vassals of empires and kingdoms of a certain size as long as those realms have low CA or Autonomous Vassals CA. Because right now, those vassals kinda get all the perks, they can conquer at will with the holy war CB, but they can't be attacked in return.