There were the Ilchi (sp) ... basically, at the beginning CBS tried to foster brotherhood along with competition. CM and CB really took advantage of that. iirc in FM: Crusader Clans we reestablished the Ilchi position for some clans.
If you're going to rewrite some of the history, I think you need to hit at some big turning point. 1. Keep Khan Schmidt from going full Ice Hellion Temper-tantrum. 2. reroll the dice on the absorption war interference ... 2a. CB really fights CSA hard instead of rolling over ... 2b. CBS warriors reflect the skill they are usually attributed. 3 CBS doesn't suck wind at the Great Refusal, perhaps they actually know how to use the combined arms they base most of their clusters after ... maybe 2nd behind CHH. 4. Go way back, CBS supports CW along with a few other clans and call out NK for what he is doing --- somehow both clans survive and prosper-ish (a heck of a lot better than they did at least).