How to set/get variables from another blueprint?

Maybe I have more complicated situation. I have 1st object which is spawned with “SpawnActor” func and from there I spawn another object which I want to somehow reference to another new BP. Also I want to get/set variable to this new BP from 1st object. Sum up, I don’t have objects in the scene, I’m spawning them in blueprints and the problem is - how can I pass objects and variables, which exist only after spawning of actor, between BPs?