I have this quoted from the RSD help file - "The membermap defines names (column A and B) and datasets (column C) for all members of this group. Columns D, E, and F specify the port members of each cable fiber. The membermap must contain all members that can exist in the variable group. The map values for members not in the group are created as spare cores or cables, but not ports. A membermap cannot be applied to a group instance if all members for that instance are not specified." This note accompanies this screenshot in the help; 
I don't understand the relationship between port members and and a fiber in a cable group. Shouldn't a fibre representing a conductor in a multiconductor cable have no more than two ports, one for each end of the fiber? I know this may sound uninformed. But, I can't seem to find any info about ports and the definition of ports with respect to fibers (as belonging to a fiber). Can anyone clear up this confusion for me?