Remotely launch files that are not part of current workspace?

edit

I'm aware of the <machine> tag which is used to launch remote nodes. However, this seems to fail when the remote node workspace is different from the local workspace.

Specifically, if I have a package "remote_pkg" in my remote workspace, but not in my local workspace (where I am calling it from), I get the following error:

  File "/usr/lib/python2.7/dist-packages/rospkg/rospack.py", line 200, in get_path
    raise ResourceNotFound(name, ros_paths=self._ros_paths)
ResourceNotFound: remote_pkg

My launch file is as follows:

<launch>
    <machine name="remote_machine" address="remote_machine.local" user="ubuntu"/>
    <include machine="remote_machine" file="$(find remote_pkg)/launch/main_online.launch"/>
</launch>

Thanks