The build XML does not have to be limited to content in one component. Ultimately all you need is to load the build coordination information e.g. build.xml or make file or whatever and the other SCM content. Once that is done the Build automation is called to act on the loaded data.

Loading is basically like loading a local repository workspace (but on an remote machine) and given a specific structure you use to load, call the loaded build files.

Set up a test system and follow https://rsjazz.wordpress.com/2015/09/30/learning-to-fly-getting-started-with-the-rtc-java-apis/ to set up the Money That Matters /JKE Banking example and have a look at the build example that is included.

Maybe follow https://rsjazz.wordpress.com/2015/10/28/build-artifacts-publishing-and-automated-build-output-management-using-the-plain-java-client-libraries/ and the referenced posts for some example based on JKE