You need to Front end these 2 forms servers using a webserver such as oracle http server.
This can be used to load balance the requests among the forms servers.
mod_wl_ohs is the module used by http server to forward the requests to weblogic forms servers.
You can use the http server component that gets shipped with the Forms and Reports installation.
How To Configure mod_wl_ohs with Oracle HTTP Server and Oracle WebLogic Server (Doc ID 1316142.1)