Please add an importing function for control towers from multiple sources for dumping
As you are able to (exclusively) assign several trucks to a control tower for exporting (see image 1) it does not currently work (exclusively) assigning a certain number of trucks for importing from several sources (e.g. storages) because the tower requires an additional excevator to be assigned to the tower (which has an own dumping zone) and thus, only results in an error message 'truck has no compatible excevator' (see image 2).
