I think we don't have to explicitly declare them. If there is such a dependency, it means somewhere in the build script of the project that depends on the other project, it refers to this other project anyway. For example
I was really worried about the multiproject problematic and I'm relieved now that there is a solution were at least I'm happy with. Of course there are many details to hammer out. But I'm confident enough now to start implementing something based on the above ideas if we all think this makes sense.