Yamaha DTXpress/DTXplorer/DTXtreme

Yes, you can get cymbal chokes using another pad, the fonction is in the
trigger menu and you don't need ad-ons pads. Personnally, I don't use this
settings(you must change the rejection settings), because cymbal chokes are
not always necessary and maybe using this process doesn't seem very natural.
But maybe if you really want to have this fonction, use an external pedal or
the hit hat pedal, it will be more practical.
vivien
PS: the rejection fonctions are discribed in the manual, you will see that
these fonctions were not created for cymbal chokes but to prevent double
triggers.