This requirement only applies to installers which support a "build" phase (i.e. create a bootable image, like an ISO from the different artifacts required):
Installers which create a build for Brahmaputra, should create the build as an "all-in-one" build. The the build process of the installer creates a single entity (e.g. ISO) - which has all the artifacts considered and required by all the projects for Brahmaputra packaged in. Or in other terms and as an example: If there are 4 different versions of OVS - all these 4 versions would be contained in the "all in one build".
The benefits are that for Brahmaputra, there is no need to deal with custom builds, there is no need for a built-configuration file, and from a release perspective, there will only be a single entity (e.g. an ISO) that would be released, as opposed to releasing a few example builds plus the components/artifcats that would allow a user to create a custom build.
The requirement of an "all-in-one" build would need to be reconsidered for future releases, where an "all-in-one" might become too big.