I think it´s very important in Arma to implant this function. I´am plaing RedOrchestra and we have it:
Audio settings
If you press VOIP key every sound of game are silenced and you can listening other players.
Actualy in Arma it´s impossible to use VOIP (or TS) when you drive any car, armored vehicle and helicopter it´s impossible any comunication by VOIP, because noise of the motor make it nonunderstandable.
Let us hope that in future that this is repaired.
Salu2