I don't know how to make events (any guides for it?), but I have a concept. If Republican Spain wins the SCW, they should have an option to align with Stalin or be independent. The former would put them in the comintern and change their political sliders, while the later would provide a boost to IC and manpower (from international volunteerism, workers control, etc). The AI would have a 60/40 chance of aligning with the Soviet Union.