Disable factory alarm? 97

Is there a way to disable the factory alarm? Problem is, if my aftermarket alarm is activated with any door open it will also arm the factory alarm. Thus, when I disable the aftermarket alarm the factory will still be active and it will blare the horn when I open a door. I attempted to put it in Japanese mode and now rather a honk honk honk...it's just a continuous honk. Which is not helped by my dual trumpet air horns that are connected to the factory 2 horns. Is there a wire I could cut or something? Thanks, Joe