I am working on a project setup and trying to understand how it will all work behind the scenes. It involves several layers of linking, material groups, and drivers.
Can I have a value in one file drive a driver on an object linked in from another file? For example: If a material on an asset within it's own file has a driver based on some custom value of a scene, how can I have it take that value from the scene it is linked into rather than the scene within it's own file?
Or, inversely, if I setup a driver in the main file, how can I have it drive the appropriate parameter of objects that I link in?
An example of this would be if each of my materials or material groups had an input for wetness. Different materials are effected differently, and will need to be setup within their own file. These assets are then linked into whatever scene file I'm composing a scene in. A rainy scene will have a wetness of 1, and a dry 0. That needs to properly connect to each material's wetness input and drive it.
EDIT: This question was originally too complex and involved several questions, I have simplified it.