Hi, I often came across this problem while doing diffuse + specular: how to keep both maps synchronized, after I made changes in one of them. This wasn't a great problem though, because most of the time I was OK with using Adjustment Layers (with simple masks) over a copy of diffuse group to get specular group. Now, in PBR…
Thank you Pior! @tynew: Lack of dynamic refreshing of smart objects in Photoshop is a problem obviously. But in complex cases it can be better than copying the layer to each group, I mean benefits could be bigger than the trouble. If you generate the specular map by using a series of adjustment layers, then you just have…