Can I set a VPN with only 1 Win NT4.0?

Can I set a VPN with only 1 Win NT4.0 LAN at one site, and a workgroup network at the other site, connected both sites to propper routers throughout the internet?
If so, how can be the server and the other site PC’s (Win 95/98) stations be configured?
Do I have to buy some other software?