You're probably looking for this vanilla/scripts/gamemodes/invasion/stage_invasion.as, methods getCommonFactionResources and getFriendlyFactionResources.
I think there's some weirdness going on here that could be handled in the *.resources files in vanilla instead. Also would make sense that these lists could be controlled with the stuff in the configurators. Would seem that this issue is limited to resources you generally want to be available for the default soldier group for all/some factions but have them disabled for the faction the player chooses for himself.
You have a few options how to get to change what happens in those methods in your mod. The first option is to simply copy stage_invasion.as to your mod and directly change these methods to fit your needs. Issues might arise if we make changes in vanilla's stage_invasion.as as the changes won't automatically apply to your mod.
The second option is to derive your own stage class from Stage, e.g.
class MyStage : Stage and override those two particular methods with implementations you require and make your stage configurator create MyStages instead of Stages etc. I won't go into details how to do that here, as I might have even misunderstood the problem

Quote:
Also on a related topic, where is the script that modifies weapons unlock for laptop deliveries (i.e. APR, Mk23 SOCOM)? Because I don't want to have these weapons in a mod set in 2035.
MyItemDeliveryConfigurator derives from a class ItemDeliveryConfiguratorInvasion which is vanilla\scripts\gamemodes\invasion\item_delivery_configurator_invasion.as, you can see something it's doing in there. Laptop unlocks appear to use
Code:
// --------------------------------------------
array<Resource@>@ getUnlockWeaponList2() const {
array<Resource@> list;
list.push_back(Resource("mp5sd.weapon", "weapon"));
// list.push_back(Resource("beretta_m9.weapon", "weapon"));
list.push_back(Resource("scorpion-evo.weapon", "weapon"));
// list.push_back(Resource("glock17.weapon", "weapon"));
list.push_back(Resource("qcw-05.weapon", "weapon"));
// list.push_back(Resource("pb.weapon", "weapon"));
// list.push_back(Resource("vest_blackops.carry_item", "carry_item"));
list.push_back(MultiGroupResource("vest_blackops.carry_item", "carry_item", array<string> = {"default", "supply"}));
list.push_back(Resource("apr.weapon", "weapon"));
// list.push_back(Resource("mk23.weapon", "weapon"));
list.push_back(MultiGroupResource("mk23.weapon", "weapon", array<string> = {"default", "supply"}));
return list;
}
You can have a similar method in your item delivery configurator class to override the vanilla behavior.