Please help me!! Simple project!

[beej]

Hello all,

I need some help realising a simple project.

I need to build a small control unit to make Instrument Bank changes in a software sampler (Kontakt2).  Where do I start??

Essentially, a numerical keypad style input system (type number then enter).

This is for a live application where I have 3 keyboard players playing through 1 computer, but need each of them to control their soundsets. How do I physically achieve the MIDI cabling/routing?

Sorry for the MIDI noob questions. Any help would be greatly appreciated.

Cheers