[CentOS] fasttest mirror -doesnt seem to pick sites near my region

> Hi Linux Advocate,
> 
> I have found this a problem for the Australian servers I manage as  
> well. I suggest you manually test the speed of some local mirrors then  
> manually specify a mirror rather than relying on the fastest mirror  
> plugin.
> 
> If your ISP mirrors content locally then that'd be the logical mirror  
> to use.


my repos are configured to use mirrorlist. how do i add mirrors manually?