Yup - with the option checked, as noted above, when you highlight a midi track, it should automatically set the midi Input Echo On to On, and when you click to highlight a different midi track, Sonar should turn it off for the track that is no longer highlighted, and should turn it 'on' for the newly-highlighted midi track.
 
You can manually turn additional midi track's midi input echo on on/off, if you want to hear a layered sound from multiple midi instruments responding.
 
Hope that helps, 
 
Bob Bone
 

Hey tindog13,
I find someone around here once in a while trying to do what you are with drum tracks that are midi recorded and want the triggered audio to be processed separately.  My answer is almost always Drum Maps.  Please go out to my website (signature) and follow through the Music - Sonar - Individual topics section, where you will find a video on how to use drum maps.  It's not terribly long and it goes over the process pretty much from start to finish and why you would want to use it.
 
Hope this helps.

Thanks guys, I have a lot to learn I know, but I try to not stop producing just because I have to figure stuff out... I've been exposed to midi for over two decades now and it still doesn't sink in so I doubt it will... I'll check out the drum maps video for sure and try all the other suggestions here. But at least I was able to keep working.

Start here, and then consider my book "MIDI for Musicians." Yes, I'm plugging my book and yes, it was written years ago, but it's still valid and oriented toward beginners. There's also a Kindle version.

Hmmm, think I'll just keep shooting from the hip, glad you guys are here though. Could not follow that video... I think I finally figured out which windows you are working in (doesn't look quite like my X3) but when I created the map the notes stopped sounding, when I tried to rename the mod it just disappeared, and I could not see where or how you were assigning the individual drums to specific panning. Just way above my familiarity level which Sonar at this point, but I'll bookmark it and possibly come back to it. Love to be able to do what you're doing in there, exactly what I'm trying to do right now, just isn't clear enough to follow. Thanks though.

Tindog13,  Yeah - that video was created with Sonar 5, so it's definitely been a while and many versions since I created it.  I've been meaning to get around to re-creating the video in the X3 software but just haven't had time to do so, especially since the drum maps themselves haven't changed a whole lot (unfortunately) in this many versions.
 
Sorry you weren't able to follow it.  If you are a midi "newbie", I imagine that it is really going a bit past the midi basics, but it IS worth the effort if you can try again to follow it.  I'm sure there are other drum map tutorials around that you could find to follow.
 
Good luck.

Thanks, Konrad!  I was wondering why no one had mentioned that setting.  I was going to post the same, but you beat me to it.
 
Kind regards,
 
Living Room Rocker