WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
As drawn it won't work. The positive half of the signal will be diverted to ground because the bias supply will, or should, be at AC ground. Just use the normal resistors for each channel and there will be no appreciable crosstalk.