Brief explanation of Listener_networks and how to configure
The following document describes how to use the LISTENER_NETWORKS setting in RAC where 2 distinct networks are configured.
How to Set the LISTENER_NETWORKS Parameter for Multiple Distinct Networks (Doc ID 2493943.1)
See also:
Important to note:  Never attempt to use a single SCAN host in a TNS alias that might be referenced by any  REMOTE_LISTENER setting.
In other words, don't try to do this.  It will not work.  
alter system set REMOTE_LISTENER="MY_SCAN" scope=both sid='*';
tnsnames.ora file entry: