In a Vulcan shop, there's typically a few parts...

1) Central Vulcan Database

2) Vulcan input station

...and possibly a 3rd, a machine running a Vulcan software based controller.

A machine can also be using a machine builder control (lockformer, D6, Hypertherm Phoenix, Burny Phantom, etc.)

If you're running the Vulcan Controller software on the machine, it can only read directly from the Vulcan database directly. 

The Vulcan input system will not typically import MAJ's from EST or CADmep. In those cases, most folks implement CAMduct for the input station, and add the "File Download" option to the Vulvan controllers so they can read the NC files produced from CAMduct instead of talking to the Vulcan database.

This replaces the Vulcan input station and database w/CAMduct but retains the Vulcan Controller software on the machines.

Trimble does have an Add-In for CADmep that converts to Vulcan...

http://mepsolutions.trimble.com/CADmep-Integration-Download-File_LP-CADmep-Download.html

This would allow you to export what would typically be in an MAJ to run it through the Vulcan database and input station.

I'm not sure if you could hack the Add-In to work w/ESTmep or not, it's the same API. I'm also not sure how well the Add-In works, when I last tried it a couple years ago, it wasn't reliable enough to consider as a production option so we moved to CAMduct for that shop and they went between Vulcan and CAMduct for a couple years during the transition.