I'm going to set up a radio desk. I will have 4 or 5 scanners and at least 1 ham radio. I prefer not to use the speakers on the units as I have a hard time hearing detail. I prefer having an external speaker. I would like to be able to hear all of them at the same time to catch a transmission. I don't want to use a switch to select a unit. Is there any way to get around having half a dozen different speakers? Thanks.