Midi map Monitor Cue in Traktor ?

Hi all

I have a midi-map-question considering how to map monitor cue on a fader (slider). The controller I working on has a slider (small fader) to cue (PFL) the decks. Slider pushed to the left is for channel 1 (Deck A), pushed to the right channel 2 (Deck B).
As far as monitoring deck A&B all works. But I also want to monitor deck C & D when switching to C&D Control (when modifiers are active). (The controller has only got 2 channels (faders), so I made 2 modifiers to switch between Deck A/C and Deck B/D controls.
I mapped the Monitor Cue('s) as followed:
Control:
Monitor cue - IN - DECK A - Button - Hold - (midi address) - M1=0 - Invert
Monitor cue - IN - DECK B - Button - Hold - (midi address) - M2=0
Monitor cue - IN - DECK C - Button - Hold - (midi address) - M1=1 - Invert
Monitor cue - IN - Deck D - Button - Hold - (midi address) - M2=1

(M1 = modifier to switch between A/C control ,
M2 = to switch between B/D control)

So now, when I slide the cue-slider to the left, I monitor Deck A (headphone in Traktor2 lights up on deck A)
Slide to the right I monitor Deck B (headphone Deck A in Traktor2 turns off and lights up at Deck B). When slider placed in the middle, both A & B deck headphones are ON (lit) on screen.
So far so good.
But when I push M1 (modifier that switches form Deck A to Deck C control) the headphone at deck A stays lit, together with the headphone lit at Deck D when I slightly manipulate the slider.
What I want is when slider is, for example, placed to the left, Deck A is monitored, when M1 is pushed, monitor (headphone) A is turned OFF and monitor (headphone) C is lit.
So: modifers OFF -> toggle slider between A & B, modifiers ON -> toggle between B & D.
Now, it does that, but A & B don't turn off when modifiers are on (and the other way around also. B & D headphones stay ON when modifiers are turned OFF).
So this is how I would want it :
Mod1 OFF = monitor Deck A
Mod2 OFF = monitor Deck B
Mod1 OFF, Mod2 ON = monitor between A & D
Mod1 ON, Mod2 OFF = monitor between C & B

All my modifiers are used (all 8), so I have no possibility to add an extra modifier.

I have also tried to map a switch button under the channel faders (a "Fader Start On/Off" switch) to toggle between Deck A/C monitoring (switch placed stand 1 = mapped to monitor cue Deck A, switch placed in stand 2 = mapped to monitor cue Deck C).
But when in stand 1 (= headphone deck A ON) and switch to stand 2 (= headphone Deck C ON), headphone deck A stays ON together with headphone deck C. Switch back to stand 1 = headphone Deck A is OFF (headphone Deck C still ON), switch again to stand 2 = both headphones OFF), back to stand 1 = Deck A headphone ON, back to stand 2 = deck C headphone on + deck A headphone also still ON, ... and so on

So when using the switch this is how I would like it:
Switch 1 in stand 1 = monitor Deck A ON (deck C monitoring OFF)
Switch 1 in stand 2 = monitor Deck C ON (deck A monitoring OFF)

Switch 2 in stand 1 = monitor Deck B ON (deck D monitoring OFF)
Switch 2 in stand 2 = monitor Deck D ON (deck B monitoring OFF)


Anybody any idea how to solve this problem ?

thx
Kristof