I see it as being like the Milan clubs. AC are 'Milan' and Inter are 'Inter'. We're 'Sheffield' and the others are 'Wednesday'.
Or 'South Barnsley'.
The parallel doesn't really work though - though I am being a little pedantic.
A potted description for those interested:
The city is "Milano".
What we call "AC Milan" are known as "Milan" - because that's their name.
Pronounced "Meelan" by Italians. Founded by mainly English ex-pats who used the English name of the city for the original cricket club and later the football club, and originally only allowed British then later Italian members.
Hence they aren't called something like "AC Milano". Other Italian clubs with similar origins : Genoa (Italian: Genova), Padova (Italian: Padua).
Re the "AC" part: You wouldn't really refer to Liverpool as "F.C. Liverpool" or just "FC", would you? - not least because it's not unique to Liverpool. Milan aren't ever called "A.C." because that just means "Football Club"... even though technically Calcio means "kick". Many Italian clubs use "A.C." as part of their full title, not just Milan.
"Inter" is just a shortened version of "Internazionale". Founded by a "Milan" rebel who thought the membership rules were ridiculous and wanted Milan to take on players from other nations - hence the name "International Football Club" (in English). The name of the city was only incidentally part of the name of "Inter" - "F.C. Internazionale Milano" (I believe that for some period of their history it wasn't even actually part of the name).
They were certainly never known as "Inter Milan" by anyone other than foreign journalists and reporters thinking that no-one outside Italy knew they were from Milano/Milan.
So two teams: Milan and Inter. Therefore, the analogy would really work only if you were referring to Sheffield FC (for Milan) and either of United or Wednesday (for the Inter equivalent).
More or less....
