im not sure how I explain this the way id like to
lets say you have a bunch of objects and you want them to act as a single texture when effects are applied to them,like the way particles + effects work. the only way to currently do this is to make them use a layer effect, or paste them all into a canvas.
of course objects out of layout would not be factored into the texture, as to prevent gigantic textures.
an effect group could be a check mark for contained objects, so that sprite A and B are in the same effect group, but even though C is contained by A its isnt part of the group.
you could also add an attribute for that object itself to be an effect group, so that all objects of its type are factored in.