No, this is not possible because in order to achieve W/D on the H90, we need to connect the dry amp to its own insert. For stereo audio, you must connect stereo pairs like Outs 1&2 or use the stereo insert from Outs 3&4. When connected for stereo audio, there’s no way to force the dry signal to one amp or the other. Add another amp, and you can do what you want.