WM is mainly to cool the intake charge so as long as you add it far enough upstream to homogenize in the intake mixture, you shouldn't NEED one injector per nozzle. Its really common in the 1.8t to add an intermediate plate between the IM and Throttle Body and inject there with a single injector solenoid.

You could do one injector placed in each IM runner, but theres so little space in the 2.0t IM (and its plastic so no welding bungs ) that there isn't really space to do it properly. If you have metal intake piping the ideal solution would be to weld on an injector bung and inject somewhere before the TB. That has the added benefit of keeping the IM and the valves from accumulating too much carbon buildup.

Also, what shick said.