In the Content Manager installation process, there is a point at which you are offered the opportunity to select port numbers and host headers for the content manager explorer and the topology manager. Unfortunately, the installer refuses to progress unless you ensure everything is running on a distinct port, while host headers ought to be enough.

So far, the only approach that has succeeded for me is to accept the quirks of the installer and afterwards fix things up manually. The number of locations where you have to fix something seems to grow with each release, so it's probably about time to just have the installer do the right thing.