We have a SharePoint MOSS 2007 installation which has two different external hostnames. When inspecting the setup I've noticed that there are two Alternate Access Mapping Collections mapped to the same web application. Each AAM collection contains one url mapped to the default zone.
I can't see how AAM collections are mapped to web apps or even how to create a new AAM collection. I've always thought that there was just a one to one mapping between web apps and AAM collections.
Does anyone have any idea as to how you would create such a situation?