In mission 3, Russians should contact you when they find out you have syberite (aka you build your first mine) and speak up about the 600sib->Barracks trade

Move the survival mission into the Soviet campaign. That way any one-offs like the 3 that already exist won't be "blocked off" by the survival one. It'll also be a great way to test your AI for modders, and it'll be probably easier to find due to being laballed as a Russian mission.