Exhausting 2 baths with 6″ ducting through one 4″ soffit vent

Will I get too much back pressure if I try to exhaust two bathrooms with a 200 cfm fan using 6 in ducting but terminating in a 4″ soffit vent… Will I get too much back pressure if I try to exhaust two bathrooms with a 200 cfm fan using 6 in ducting but terminating in a 4″ soffit vent…Read MoreGreenBuildingAdvisor