Each element of first or second source may have differentiated Segmentation.
The third category materials do not have segmentation by default, having CBR = 100, Expansion = 0 and Permeability = 0. If you want to force the use of segmentation in third category material, enable it in the Settings tab, the third category segmentation. See the example below:
If sources share the same target, this should occur in most of the times, you can fill in only the Segmentation table.
If there is a need to overwrite the Segmentation table for some item, you must fill in a table for each item of source with this need.
The table to be populated is identical to the Segmentation table.