I havn't used genesis to any reasonable extent. but in general I can tell u, not all emulators are netplay enabled.
I don't know of the most recent emu's, but some didn't have the feature built in at all, sometimes u needed a plugin, or sometimes it was included by default. If the emu has netplay ability the instructions are included in its documentation folder. In general connecting is going to be the same as any other online PC game.
I'm guessing u were experimenting with logmein Hamachi because there is no netplay option in the emulator ur trying to use. I never needed to and never tried that, and i could be wrong but my guess is a vpn app like that is not going to work for games, or maybe it will be laggy. U sound like a complete newb, let alone not including networking/vpn. so to save u a little time, ill point out the most likely things u need to watch for after u have the proper applications and know what ur trying to do... are Port forwarding on your Router, and any Firewalls on your pc's. those are the most likely and almost always the only newb issues encountered.
If theres firewalls, the apps always need to be allowed access threw it.
ports don't always need to be forwarded on modern routers, cause UPNP seems to be always on by default... but I personally think its worth everyones while, to disable it and forward the port yourself, as UPNP is a whore and worthless network overhead. usefull in general tho for non gamers who need speratic random access like VPN, not games.
