Issue with materials get affected with the same setting


I’m having an issue after importing my project from Sketchup to unreal. For example if i select a TV Screen image and make it Emissive, all my materials 9 walls, floors…) get emissive and so on. Even if they have different names/textures. Could you please help? I’m using U5

( I think they are related to the parent which i don’t know where to break this relation)