I would go as far as saying that this simply cannot be done without changing what is hard-coded. The simple fact, there is no way to create variables in the inis. This would mean that if you a garrison that building with, for example, 2 rangers and a missle defender, the game would not understand that it needs to frop specifically 2 rangers and an md. However, it might be possible to use this as a scripted thing in a map, although, i know little about worldbuilder...