Sub Voice Chats

So I've been playing destiny and found an increasing need to seperate groups when doing raid encounters. This is easy but we need to still know of what's going on as a whole. 
It would be nice to have sub voice chats that can hear the others at lesser volumes.
eg.

Voice Chat 1
Sub Voice 1 (70% Volume) < If I'm in this one, I'm 100% then the one below is at 70%
Sub Voice 2 (70% Volume)