Unit Reflective IR is a port B unit (black connector). So in order to connect multiple units you'll need a PbHub. (The b stands for port B.)

(A PaHub is meant to connect multiple port A units (red connector) aka I2C with the same I2C address.)

I created an UIFlow2 example to read three Unit Reflective IR via PbHub in UIFlow2 Project Zone called M5AtomLite_Three_ReflectiveIRUnit_UIFlow2.4.2

Note: The example is how I think three reflective IR units can be read via PbHub. But actually this method is untested by me as I do not have the necessary hardware.

Thanks
Felix