One of my favorite podcasts on blogtalk could use some help. When they take phone calls, it seems one audio stream/source takes precedence over all others and this can create quality issues for those who listen from a phone (when two people are talking at once you cannot hear what either person is saying. Whereas when I've called AM sports stations this doesn't happen)

Is there a piece of equipment needed that can sort this issue out, or is this simply a blogtalk limitation?