A little more context would help, like are these actors already spawned or are you spawning them? You can make a variable for this in the actor “instance editable” and expose on spawn" allowing it to be passed passed and set in a loop. If they already exist you want to call “get all actors of class” and use a could nested for each loops to set the value based on element index.
Also, are all these actors of the same class? If so you could again call l all actors of class then run a nested for each loop, and match the index numbers to set a variable on the actor. If they are of different classes, you may consider using a Map variable, of class references to your desired attribute variable.
Hope this helps, for more advice perhaps give us more detail and possibly some screenshots of code so the community can better understand what you’re trying to do