Are you saying they have a single amp circuit for the TC and mulitiplex it to to the sensors to collect the readings? If so, I wonder if HM could be adapted slightly to use its single TC Amp circuit where the ports could be externally multiplexed and time divided for readings. For example, the HM could could be added with a how many external thermocouples are you using feature and then it could time split the readings sending a signal out the RJ45 jack to control the external multiplexer chip that switches the TC sensors which feed their data back to the currently existing TC port lines.