This post should give you an idea to meet your requirement. Only difference is the latest OHS (Oracle Http Server) is Nothing but former Apache Http WebServer used as front end for Weblogic Cluster.
What you want is totally possible using OHS (apache http webserver). You can redirect to different backend servers based on front coming url pattern at apache.
Most of the customers standard environment is have a Clustered Weblogic Domain with 1 Admin and multiple managed servers across different machines. These are all inside company firewall. Then they will have Apache Web Server in front outside of Firewall. This Apache Host, Port (default is 80 which we don't need to type in url also) is exposed to end users with proper webcontexts like http://apachehost:apacheport/myApp1. Within a .conf file on Apache side, we define redirect details if the input path patter is like /myApp1 to which backend cluster it should go to. If input url pattern is like /myApp2 it may go to totally different weblogic cluster domain itself. So its like one Apache Web Server with proper configurations can take care of all the applications across all the domains of weblogic.
Apache Front End is used by many customers and infact this is exactly is what branded by Oracle as Oracle Http Server (this is nothing but Apache only).
Using Apache you are going in the right direction.