BleepingComputer.com: How Do I Loop Sound Output?

Ok...

I've got a Dell Vostro 200 with rear panel jacks for front/centr/rear speaker SurroundSound and RealTek HD Audio Manager...

I play on CombatArms, an online, team-based First Person Shooter put out by Nexon (nexon.net, they also run DungeonFighter, MapleStory & Vindictus).

Game sounds come thru standard Audio Out jack, and you can talk to team members thru Mic/Line in with "Mic On/Talk" toggle being key-mapable...

Headsets are VERY popular...

I have a CombatArms Playlist on my Windows Media Player, which I run while in-game. Output thru standard Audio Out Jack.

I have the various volume settings (System Master Volume, Media Player Volume, Game Sounds Master Volume, Sound Effects Volume and VoiceChat Volume) adjusted so the gunfire (gamesounds) is BARELY audible over the music and team members (VoiceChat) are SOFTER than the Lead Vocals but LOUDER than the Back-up Vocals of the bands.

Here's what I'd LIKE to be able to do...

I want to loop the MUSIC output to the Mic/Line input THRU the "Mic On" toggle key so that whenever I hit (or hold) the "Talk" button the music is ALSO broadcast to my team...

I tried a basic 3.5mm splitter but it caused an echo effect when team members responded. I assume this was caused by the fact that game sound AND music are coming thru the same jack...

Is there a way to separate those two signals so I can inflict my musical tastes on my team mates?

Thanks