You need to detect something like ROOT_SOURCE_DIR in your build_makefileN.mk

ROOT_SOURCE_DIR:=$(abspath $(dir $(filter %build_makefile1.mk,$(MAKEFILE_LIST))))

And then include intermediate makefiles relative to this directory:

include $(ROOT_SOURCE_DIR)/common/other_dir/...

See also https://github.com/sergeniously/makeup/blob/master/makeup/.mk