OK, sorry, maybe I expressed myself misleadingly.
First of all: I'd lke to assign MIDI Parameters by Mouse and Key, not by moving any Software or Hardware Controller. I usually know which few Parameters I'd like to choose, and in some special Situations I haven't got a Hardware Controller and would take too much Time to change everything by Creating Controllers in the DAW just for that. OK, again, using Mouse and Keyboard to assign MIDI-Controllers, is this understandable yet?
Second: If I assign a Controller the usual Way I have to assign the MIDI Channel together with that. But sometimes, by using more than one Keyboard with different MIDI Channels I need Parameters of an Instrument to be controlled by both. (Solution: MIDI Channel ALL instead of 1, 2 or whatever). Example: I use two Keyboards and a Pedalboard for the B-4 (different MIDI Channels, of course). Now I want to control Leslie Speed Change by Aftertouch. Now I have to choose if I control that by the Upper or the Lower Keyboard, but I cannot control it by both because the Aftertouch will only respond to one MIDI Channel instead of ALL. The Solution would be to make it possible to simply change that by Mouse and I might be happy, OK?
The other Solution would be to make it possible to assign one Parameter (here: Leslie Speed Change) to more than one Controller (here: Aftertouch of Channel Keyboard-One PLUS Aftertouch of Channel Keyboard-Two). But one of these Solutions should be possible to make it work at all.
I cannot find any of these Solutions in any Manual, so is this possible ... that's my Question.