* project.testing.com
* project.staging.com
* project.com
So I had created a domain lookup service that when passed the request URI could work out what site the request for targeting.
def targetUri = request.getServerName()
I did a lookup for that target name against an object stored in the database relating to that targetUri and passed that back, making it available for queries for the correct data to show, and passing that down into the views to render the relevant CSS and Javascript files.