By “load” do you mean reference them in a

dependencies=

of a target? No, you have to enumerate every dependency.

src/scala/blah::

is just for specifying targets to act on in command-line invocations. I can see how being able to do this might be useful, but on the other hand it’s likely to cause unnecessarily coarse-grained declared dependencies, which is undesirable. In the long-term we (or at least I…) want to move away from manually-maintained BUILD files towards inferred dependencies (via static analysis, say). There are already various “buildgen” efforts in various stages of usability.