Bazaar仅合并与主线共同的文件

I am currently working on a project that has two phases, one of which is to be dropped later on. Development for phase 2 must begin, but bug-fixes for phase 1 will be on-going during this time. I want to branch from the phase 1 repo to start on phase 2 work, but many of the files will no longer be needed. I need to integrate any changes made into the phase 2 branch, but i dont want the hassle of repeatedly removing files that are no longer relevant to me, in otherwords i only want to merge changes where we have files in common. I am currently working on a project that has tw