Well, we were actually considering this feature before — it’s called sequential groups. A station can be assigned into a sequential group such that all stations in the same group are serialized while stations of different groups can run in parallel. The feature isn’t implemented yet, because we consider it to be somewhat an uncommon feature. We will still consider it for the future, but it has low priority since not many users seem to need it, and implementing it might complicate the user interface for those who don’t need this feature.