Not in BP, was far as I’m aware 
Calling in a loop or parallel is not an option, as we don’t know when a load is going to happen. The loads, and callbacks, all happen in a totally unpredictable sequence.
The simple actor handles it very elegantly in BP. I know some people are allergic to spawning an actor for this sort of thing, but when you’re already streaming a level, I don’t think one more actor will do any harm 