Silence Detection in conference


Is there way to detect the silence and audio enery level in asterisk conference bridges? if there is continous silence or less audio level from moderator, the participants should switch to another conference call… how can i achive using asterisk.

I dont have any hardware cards (TDM/E1) cards in the asterisk, all i have SIP account configured from broadvoice SIP provider.

Please help on this and thanks in advance…