Windows Authenticating to NIS Servers?

Nericus asks: "I'm in the process of linking four separate networks via VPN. Each has its own little DNS sub-domain (lazy, quake, sector13 and overkill) with each possessing its own little branch of resources, here's the problem. I'm looking for a way to authenticate to a server (NIS) in each domain so the owners can have access control to the various resources. The problem lies in the fact that a decent chunk of the machines are running Windows 95, 98 or 2k (no flames, please) and I can't find a simple (re: cheap/free) method of authenticating Windows to a NIS server, M$ seems to think that Unix boxes should authenticate to a Windows box that'll emulate a NIS server, but won't authenticate TO one without third party software. Any suggestions would be greatly appreciated (P.S. Yes, I've considered having them authenticate to Samba, but that's a less than elegant solution from what I can tell) "