that sounds like a nice idea... although perhaps this is too simple? of course it depends on the amount of "activity" you need... maybe this could be made into a kind of mini-campaign (the whole thing would need some kind of scripting anyway, so why not a bit more complicated?):
if certain requirements are met
1) perhaps you need some kind of research prerequisite... psi research should be completed, I guess
2) a certain amount of xcom activity in the country?
3) maybe you need to capture and interrogate an alien from a UFO originating in that country?
4) ...?
then after a while, a special mission pops up: "pick up spy"
kind of like the "recover VIP" missions in XCOM2012: an alien-infested map with a single civilian somewhere - kill all aliens and/or get the civilian into your exit area (aka transport craft), because he/she has gathered intelligence on how the aliens control that country.
if that mission is successful, you obtain the location of the alien/government cooperation facility within the occupied country's borders, which is what you described above.
the complicated part is that however we want to implement something like that, it needs a whole lot of extra mechanics, that allow for scripting or script-like behavior.
