I believe that you can, but you must set up the install accordingly. I'll elaborate.
I have all three of Third Wire's second gen titles. You're probably aware that if you install them in order, every successive title merges with it's predecessors. Every title also creates it's own sub-folder within the main mod folder. Every sub folder contains the full planest (SF2, SF2V, SF2E). Now, one normally runs the whole mess off of the first game's .exe file, and therefore has access to all terrains and eras.....well,
I've deleted all the unnecessary objects (including aircraft) from my SF2V sub folder. I've also created my own VietnamSEA_nations.ini, with limited nations (but to which I've also added the Khmer-Rouge and Pathet-Lao).
In order to use all this...you have to run SF2V as a standalone, using it's own .exe (and not the SF2.rxe). Despite being a standalone, it still resides within the same folder structure as the other titles.