Hmm, and just using higher level of relationship to reference everything from some Unit/Service by just right click on it in the same manner as with pipelines would not accomplish the same goal? You can also select multiple items in the items tree by holding CTRL or SHIFT keys and reference it out in one go as well:
As for the VBA approach, I believe that would not be easily done. There is no direct key-in to copy out OPMS components by some relationship as the operation is quite complicated.
Regards,
Justinas