Check out this YouTube to see a demonstration.
This Arrangement Template contains 3 Device Racks: Kontakt Multi 1; Kontakt Multi 2; Kontakt Multi 3.
Each rack has a Kontakt Instance loaded with 16 empty instruments.
The user will open the Kontakt plugin on each rack, and then load in his own Kontakt Multi to populate it with his chosen instruments.
The user then goes to the structure page and can rename each track to match the corresponding Kontakt instrument, add an articulation map, and adjust the instrument ranges if necessary.
The final step is to save the Arrangement as a Template to use on future Synfire Projects.