Depends on facilities of the various units. You will need THRU connectors if you want to daisy chain.

As well as that, you will need to be able to use different channels to carry different information. Hence the playing unit uses a spacific channel, and the receiving unit is set to respond to ONLY that channel. and disregard other info. Another pair of units must use a different channel. There are units that can be set to receive data on a specific channel, but I'm not sure I've seen anything that can be set to transmit data ONLY on a specific channel.

I don;t think that data can be split by note (key number) but maybe some devices can?

If you check the options on the devices you wish to use, there may be combinations available.

Geoff

Your question is a little bit confusing. You stated... "Yamaha controls the upper keys and the Kontakt controls the lower keys"?

1- Are you trying to use those two keyboards to control VSTs?

2- It sounds to me like you are trying to use what would normally be considered a "keyboard split" when you are using just one keyboard as a controller. Since it sounds like you have two different controllers, the use of a split is not necessary.