Reset actor in loop after changing materials (Graduation thesis, help please!)

Hello everyone, I’m working on an architectural visualization for my graduation thesis and I’m trying to create a blueprint that allows the player to make other actors disappear by pressing a button. As you can see from the images, pressing B the group of meshes “BasamentiNeri” disappear (I’ve created a material that, from a black marble texture, becomes “invisible”, and then I’ve disabled collisions), and pressing L the group of meshes “CopiaBasamentoNero” (consisting in the same meshes, duplicated, made invisible at the begin and placed in the same position of “BasamentiNeri”) appears (I’ve created another material that, from “invisible”, becomes a black marble one, and then I’ve enabled collisions). This works, but, when I try to loop the button press, it fails to reload the sequence of events linked to the change of materials and the group modifies only its collision.

Is there a way to reload the actor and the material after pressing B and L the first time, as if nothing had happened? I hope so. Thanks to whoever will help me.

PS: I tried to ask the same question in the AnswerHub months ago, but the problem remains, and I’ve no more ideas >-<