Ok - let’s add some modifiers to start with.
Slot 1 button: Add In > Modifier > Modifier 1
M1 / condition M1=0 / type=button / mode=direct / value=1
M1 / condition M1=1 / type=button / mode=direct / value=0
Slot 2 button: Add In > Modifier > Modifier 2
M2 / condition M2=0 / type=button / mode=direct / value=1
M2 / condition M2=1 / type=button / mode=direct / value=0
Slot 3 button: Add In > Modifier > Modifier 3
M3 / condition M3=0 / type=button / mode=direct / value=1
M3 / condition M3=1 / type=button / mode=direct / value=0
Slot 4 button: Add In > Modifier > Modifier 4
M4 / condition M4=0 / type=button / mode=direct / value=1
M4 / condition M4=1 / type=button / mode=direct / value=0
Once added, press those buttons and watch the modifier state display (yes it’s that tiny 8 slots in the controller manager)
each slot will show the currently selected/activated value for that modifier. If all good, your first 4 slots which is M1 to M4 should toggle between 0 and 1 by each button press.
That’s the “hard” part 
Now we’ll get on the cell trigger part, trick is to assign proper modifier conditions for each of this trigger commands:
Slot 1 Cell 1: M1=0
Slot 2 Cell 1: M2=0
Slot 3 Cell 1: M3=0
Slot 4 Cell 1: M4=0
(This way we tell Traktor to start the samples only while the modifiers are negative)
To stop the sample we will use this command: Add In > Remix Deck > Slot Stop/Delete/Load from List
Slot 1 Stop: M1=1
Slot 2 Stop: M2=1
Slot 3 Stop: M3=1
Slot 4 Stop: M4=1
(notice how all modifiers are positive now - in other words your sample is being on play when the modifier value is 1, next press decreases the modifier value back to 0 and stops the sample at one time)
Use the same principal to your second deck.
If you run out of the modifiers you can add new generic midi device to the mapping which brings you another set of 8 modifiers.
Wish you luck with testing this! Feel free to ask more, I might miss something 