I'm forming a Joint Venture with another independent consultant. Am I correct that if we want to conduct meetings where BOTH of us are on it and the availability checks BOTH of our calendars, I'd have to upgrade to Agency? Or can I simply connect his calendar to my account and have the availability look at two calendars? Will he need an email address on my domain to use it or may we create a sub-account (using his business email) under my Administration and he'll have full access (and maybe even use it for his own independent work)?