How to interact with actor when it is in hidden level

I am trying to create material and level changing option. I have created theme packages which player can change in game and also able to change different levels. But whenever I change theme package it changes only in the visible levels not in hidde levels. But i want the same material applied in all levels either they are visible or not. I am stuck here.
Please guide me how can i solve this.

it depends on your actual design how did u do it inside the blueprint.

I would suggest the following.

  • Store all actors of all levels in an array .
  • On each item, change the material based on user selection.
  • For better optimization , store the material itself based on user selection, once the level is load apply this material to all actor inside the level .

Thanks for your answer. but i have not used Array yet and i dont know how can i store actors in array.
i am writing all my codes in persistent level. Please also tell me how can i store materials in that you mentioned in 3rd point. i am attatching my codes how i am doing it.