This plugin is a external talk notification script. Users with the "Access_Reservation" flag (a) will be able to toggle this command. What will happen is that all users with "Access_Reservation" and above will see a message saying that user is talking over Ventrilo or Teamspeak. CS:S support for right now.
Min: Sourcemod Version 184.108.40.2064
For the client to do this they need to bind their Teamspeak or Ventrilo key to "sm_exttalk".
bind <KEYHERE> sm_exttalk