It'd handy to be able to pass down metadata about the parent build that triggerred off the current build. This will allow the information to be passed into the build process (e.g. Maven) to use this information to chain their builds.

So you might have:

dependency.parent.0 = JRA-MAIN-102
dependency.parent.1 = JRA-UNIT14-56
dependency.parent.2 = JRA-FUNC14-12

where JRA-MAIN-102 is the originating build that kicked off this entire tree. We could even add some extra tool to show this graphically

bamboo.dependency.parent.0 would be available to the underlying build process where it could be used to retrieve artifacts or extra information about the originating build.