The buddy building is in the next county. If it was in your county then it wouldn't be a buddy, it would be a neighbor. You're aware of this building, but they aren't that close, so they're just a buddy.
Your county is everything you can reach when shooting a gun (ぐん). If the bullet can't reach a building you know, it's a buddy building in another county.
Currently there are no similar looking kanji which exist in the WaniKani learning system