BP controlling multiple MI

Hi there,
i am still a UE-Noob hance this question:) I have one ArchViz Level which i would like to render as a sequence. The basic concept is have some nice camera moves and to show sequentially all the components of the environment by fading them in one by one. I have adapted one Disolve Effect for this purpose. My problem is that i have tons of Material Instances using the same FadeIn effect and i don’t want to animate in the Sequencer the scaler for every each one of them, so i need one Blueprint to controll all the materials.
Any help is highly appreciated!

Cheers,
Boris