Additional Public IP Required?

I currently use waf for owa and active sync; all working well using https. I have a new request to allow access to a remote desktop gateway which also uses https but of course a different certificate and internal server. Question - is a second public ip going to be required because both are using https? Wasn't sure if each having different certs with different domain names on the certs would be sufficient.

One other question - I presume that if I decided to not use waf but a dnat rule instead for the RD Gateway that an additional ip would be required. Even with that wouldn't that break the waf rule for owa/active sync since the dnat rule would be used first (listening for https requests) when users tried using owa or active sync and be directed to the RD Gateway server?

Thanks