It is currently not possible.
Please consider it in the future versions of B4X tools.
Possibility to use B4X as a cross-platoform tool is one of the most important competitive advantages over native tools.
Before I kept sources for B4A, B4i, B4J in separate folders and it was really nightmare to sync changes between modules.
Now I keep all modules (modules, classes and Subs have the same names for all B4A, B4i, B4J) and I am able to compile app for different plantforms just switching to another project file.