There's no hard-and-fast rule; it rather depends on what you want to achieve.Cable and Dogleg objects have been designed to represent a single discrete signal path (i.e. one pair, in this scenario), so I would use one Dogleg or Cable per pair and use a common value e.g. Multicore01, as the CS_Name attribute for each 'pair' in the multicore.
When you output to a report e.g. Cable + Connection Schedule you could then sort, filter or subtotal by CS_Name in Excel.
Does this help, or have I missed the point?