[otrs] Restrict Visibility to Only Customer Interface

Hi all, I am trying to setup an otrs system with two separate interfaces (internal and external). I need to have the external interface locked down such that only customer.pl is evident and the others are hidden (404). The external facing system is on its own machine on our DMZ and is pointed at the internal MySQL db. The internal interface is on the same machine as the db. Is there a way to easily prevent users from accessing the other login pages without affecting the customer interface operation? Would it be sufficient security wise to: A) mod_rewrite index.pl to customer.pl B) deny installer.pl, public.pl and rpc.pl Thanks!