In case you need it too: Configuring SSL Host Headers shows you how to get up and running with one IP, port and certificate but multiple host headers. All you need is a wildcard certificate (learn more here) and some CLI magic because there is no UI for it. Basically, it boils down to (for example):

adsutil.vbs set w3svc/siteid/SecureBindings ":443:host.wildcarddomain.com"