Assuming they're running on 14V, you need an extra 0.68Amps per globe. So that corresponds to whackin a ~18ohm resistor in parallel with each globe. That is, if my brain is functioning properly. Take note though, at that kind of current it's gonna have 11watts in heat to dissipate, so you'll need a big mother of a resistor or have a few smaller ones in parallel, else it'll just burn out pretty quickly.