That would go against the very principle of inifiles. Inifiles are used to save settings, etc. If you want to save multiple settings, give each setting a different name.
Seeing how your section is named Favorites, you should store your info like this:
[Favorites]
server1=1234
server2=2345
server3=3456
Also, I'm not even sure what you want is possible, since the ini file format is defined by Windows, and not mIRC.
