I want to use an Android phone as a replacement for a conferencing phone. Is there hardware I can buy to help facilitate multiple people around a table hearing the conversation and also being heard when they each speak? I can buy a bluetooth speaker to project the voice(s) on the other end of the call, but I worry that this sound will then echo back to the microphone and create problems of echo on the destination side. How do I solve the problem of getting everyone's voice to be heard when they cannot all huddle around a mobile phone in speakerphone mode? Maybe there is a way to have multiple external microphones all feed to the phone through a splitter?