Elektron Musical Instruments

Besides unplugging the midi cable, is there an easy way to tell the
MachineDrum to stop sending NOTE ON and OFF messages downstream? 

Can I use a midi machine to send such messages but have no other tracks
do so?

How do I make different tracks send to different midi channels?

I'm thinking about the track mute feature and wondering if I missed a
"midi mute" page somewhere. 

Thanks,

-M@