*Introduction to problem*:

I have a project that uses *Akka* and *Spray* that logically consists of two parts `A` and `B`. In the final version both of them will work together, exchange messages etc. At the moment I have implemented some functionality of part `B` and whole part `A`. If I run `sbt compile` not strangely I get errors that refer to part `B` only. 

*Question*:

Is it possible to define some rule for `sbt` that will compile only modules that build part `A` exclusively ?