This can be achieved by using two in-line heaters (e.g., two SH-27B) and a dual channel temperature controller. Basically, split the incoming flow line into two just prior to the in-line heaters (one heater per line) and then rejoin the lines before delivery into the chamber.

Another approach would be to use a single SHM-828 in-line heater (contains eight independent perfusion lines) and a single channel temperature controller.