Specify METEOR_PACKAGE_DIRS for each meteor instance / Project

[abate]

Since I work on multiple projects at the same time, each one with a different set of custom packages I run meteor as METEOR_PACKAGE_DIRS=../packages/ meteor . I haven't found a way to use meteor-helper in the same way. Would it be possible to add this env variable to the meteor exec environment, and maybe configure it per-project ?