Right approach to change materials of actors by widget

Thanks for the reply.

I made some changes in the setup, see attachments and the widget appears when selected the right actors of a class, that works well.

Only thing I can’t get working is the material change, it changed the staticmesh0 only and not the others when selected. I have placed all the actors in one BP class and set the material slots right.

What have I done wrong or has just to be done?
Thanks in advance!!