I need a pizzicato cello as my 17th instrument so I inserted this into my Kontakt multirack.  On track 5 (a legato violin part that uses MIDI Channel 5) there is a section that is vacant at bar 85.  So I created track 17 for the piz cello that starts at bar 90 and goes for 15 bars - the violin part doesn't return.  So, essentially, two different tracks with two different instruments sharing the same MIDI channel.
 
In Kontakt, on the instrument panel, I assigned Pizzicato Cello to "st.17 [2 ch. routed 33/34]" and the MIDI channel to "[A] 5" - obviously Channel 17 doesn't exist.  In Sonar, MIDI track 17 is assigned to "5:Koontakt 64" - Kontakt's channel 5 (I renamed my "Kontakt 5" Synth to "Kontakt 64" to avoid the 3 Kontakt 5 outputs confusion) and the corresponding Audio track, Track 33 is assigned to "kt.st.17 Stereo".
 
However, both tracks 5 and 17 are playing both instruments.  Where is my error?  How do I get track 5 to play just legato violin and track 17 to play just pizzicato cello?  Neither instrument is overlapping.  How do two instruments share a midi channel?   

In the same track, Insert a Bank/Patch change?

As I know 2 different instruments cannot share a MIDI channel.
For 17 ... 32 you need a second instance of Kontakt.

Does Kontakt come with (or have you purchased) a key switched string section, violin, viola or similar?

Thanks Greg.  All I see are patch options of 1-127 on Bank 0.  Do you know where I should look to find the number for my pizzicato cello?  Where I assume patch number 0 is has my top instrument "a-violins 1" but the rest are just numbers.  Is this a Kontakt thing or a Sonar thing?    

djwolf
Thanks Greg.  All I see are patch options of 1-127 on Bank 0.  Do you know where I should look to find the number for my pizzicato cello?  Where I assume patch number 0 is has my top instrument "a-violins 1" but the rest are just numbers.  Is this a Kontakt thing or a Sonar thing?    

Well, I've never used Kontact, so I'm not sure how to make the banks and patches available in that dialog. Maybe an Instrument Definition? A lot of folks here use Kontact so maybe they will know.
For now, another instance of Kontact would be your best bet.

It's funny after all these years I've never figured out how to insert a patch change in the middle of a song. 
I would think the event list would be where I might do this but PG don't seem to show on the event list. 
Myself I just would use a second instance of the player. 
 
I know I get downloaded midi files that have PG changes mid song and TTS-1 seems to have no problem. 
They show on the track pane but I've never figired out how to edit them. I end up opening the song in another sequencer where they show on the event list. 
Sonars patch changes are all handled in the track header as far as I can tell and there is no other options. 

"It's funny after all these years I've never figured out how to insert a patch change in the middle of a song. 
I would think the event list would be where I might do this but PG don't seem to show on the event list. 
Myself I just would use a second instance of the player."
 
Insert-Bank/Patch Change (Top Line, between "Views" and "Process").

Thanks, that seems to answer the OP's question as well.