Swapping one building for another one (both vanilla)

[Teleklos Archelaou]

I'd just like to swap some buildings around. I don't want to edit the actual cas files or anything like that, but I need to know how one would (for example) make egypt culture (vanilla terms), or specifically the egypt faction I should say, have a barbarian building instead of an egyptian one. Let's just take a barracks for example.

I don't want to change what the barracks does, or what the icons even look like on the strat map, when you highlight the city. I just want to "redirect" it, so that instead of throwing the battlemap egyptian barracks into the town, it throws the battlemap barbarian barracks in there instead.

I would think that maybe a text file can be altered to "redirect" appropriate cas files, but I have never altered these before.

Any tutorials or anything that could help me achieve this? Any help would be much appreciated.

--------
edit: my example was just one building, but I'd like to make (for example) all egyptian variants of buildings use barbarian variants instead.