I have two bathrooms on the second floor of my two storey house. I only have one exhaust pipe going out the roof. Currently only one exhaust fan in the bathroom is connected to that pipe. The other exhaust fan has an flexible hose going to the attic only and that might cause moisture problem in the attic. I want to connect both exhaust fans to the same exhaust pipe with a T-connector. I am not sure if the existing exhaust pipe can let all the air from both hoses going through. So I plan to install an in-line duct fan to improve the air flow, hopefully that might help. But I don't know how to turn on or off the in-line duct fan from the switches that I have already installed in both bathrooms. Is there a way to control the in-line duct fan and the exhaust fans that are already installed in the bathrooms from either one or both bathrooms (without installing another 3 way switch for the in-line duct fan) ?
Thanks for your help in advance. I look forward to your reply. Ming.