[Vince]

You can, in fact, access the file you need but you'll need to filter out the buildings you don't need. In the data\maps directory and its subdirectories you'll find IPL files. You can open those with notepad. Scroll down to the header 'enex'. The entries have rather cryptic names, but I think it's safe to assume that something like "SFHSS1" means "San Fiero House 1".