Consolidation of apps onto one server with multiple nics

Hello,
I am looking for information on best practice/approach. Recently we have consolidated 9 different applications that were running on their own respective workstations/servers. Now all the applications are hosted on one main RHEL server with 6 active network interfaces.

So having said all of that, My question is regarding RedHat server tweek or tuning ... Is there a way to tune Redhat to know that all these apps are hosted and not have to send the information down the wire and back again through another interface ? I am by no means a programmer and if this falls in the realm of rehashing application(s) so be it, but then again if I am able to define something on the server maybe in NetworkManager or kernel ... I am willing to learn and try.
Thanks.