fins - maybe you are thinking of NetBEUI? NetBIOS is routable as a session service both in its native form and over TCP (NetBT), however its name resolution service isn't routable unless you have NBS/WINS server, as it just uses broadcasts. Course you could enable subnet broadcast forwarding on your Core but I wouldn't recommend it. If the only thing you are having problems with is the name resolution then the host entries are probably the best way around this, unless you can turn off NetBIOS altogether and use TCP connections in conjunction with DNS!
i second that. If you are out for pain (and some say there is no gain, without) you could run a WINS server. Samba4WINS even supports replication